The American entry into World War I came in April 1917, after more than two and a half years of efforts by President Woodrow Wilson to keep the United States out of the war. Apart from an Anglophile element urging early support for the British, American public opinion reflected that of the president: the sentiment for neutrality was particularly strong among Irish Americans, German Americans, and Scandinavian Americans,  as well as among church leaders and among women in general. On the other hand, even before World War I had broken out, American opinion had been more negative toward Germany than towards any other country in Europe.  Over time, especially after reports of atrocities in Belgium in 1914 and following the sinking of the passenger liner RMS Lusitania in 1915, the American citizens increasingly came to see Germany as the aggressor in Europe.
As U.S. president, it was Wilson who made the key policy decisions over foreign affairs: while the country was at peace, the domestic economy ran on a laissez-faire basis, with American banks making huge loans to Britain and France — funds that were in large part used to buy munitions, raw materials, and food from across the Atlantic. Until 1917, Wilson made minimal preparations for a land war and kept the United States Army on a small peacetime footing, despite increasing demands for enhanced preparedness. He did, however, expand the United States Navy.
In 1917, with Russia experiencing political upheaval following widespread disillusionment there over the war, and with Britain and France low on credit, Germany appeared to have the upper hand in Europe,  while Germany's ally, the Ottoman Empire, clung stubbornly to its possessions in the Middle East. In the same year, Germany decided to resume unrestricted submarine warfare against any vessel approaching British waters; this attempt to starve Britain into surrender was balanced against the knowledge that it would almost certainly bring the United States into the war. Germany also made a secret offer to help Mexico regain territories lost in the Mexican–American War in an encoded telegram known as the Zimmermann Telegram, which was intercepted by British Intelligence. Publication of that communique outraged Americans just as German U-boats started sinking American merchant ships in the North Atlantic. Wilson then asked Congress for "a war to end all wars" that would "make the world safe for democracy", and Congress voted to declare war on Germany on April 6, 1917. 
U.S. troops began arriving on the Western Front in large numbers in 1918.
- 1 Main issues
- 2 Public opinion
- 3 Preparedness movement
- 4 Decision for war
- 5 Public opinion, moralism, and national interest
- 6 Declaration of war
- 7 See also
- 8 Footnotes
- 9 Bibliography
- 10 Primary sources
- 11 External links
Britain used its large navy to prevent cargo vessels entering German ports, mainly by intercepting them in the North Sea between the coasts of Scotland and Norway. The wider sea approaches to Britain and France, their distance from German harbours and the smaller size of the German surface fleet all made it harder for Germany to reciprocate. Instead, Germany used submarines to lie in wait for, and then sink, merchant ships heading for enemy ports.
The United States insisted on maintaining the traditional rights of ships registered in neutral countries and protested strongly against American ships being intercepted or sunk: the British seized American ships for supposed violations, while the Germans sank them — often without warning, in violation of international law that said sailors must be allowed an opportunity to reach their lifeboats. After several violations, Germany stopped this practice but in early 1917 she decided to resume unrestricted submarine warfare, in the hope that this would starve out the British before the Americans could make any effective military retaliation.
The British Royal Navy successfully stopped the shipment of most war supplies and food to Germany. Neutral American ships that tried to trade with Germany were seized or turned back by the Royal Navy who viewed such trade as in direct conflict with the Allies' war efforts. The strangulation came about very slowly, because Germany and its allies controlled extensive farmlands and raw materials. It was eventually successful because Germany and Austria-Hungary had decimated their agricultural production by taking so many farmers into their armies. By 1918, German cities were on the verge of starvation; the front-line soldiers were on short rations and were running out of essential supplies. 
Germany also considered a blockade. "England wants to starve us", said Admiral Alfred von Tirpitz, the man who built the German fleet and who remained a key advisor to the Kaiser Wilhelm II. "We can play the same game. We can bottle her up and destroy every ship that endeavors to break the blockade".  Unable to challenge the more powerful Royal Navy on the surface, Tirpitz wanted to scare off merchant and passenger ships en route to Britain. He reasoned that since the island of Britain depended on imports of food, raw materials, and manufactured goods, scaring off a substantial number of the ships would effectively undercut its long-term ability to maintain an army on the Western Front. While Germany had only nine long-range U-boats at the start of the war, it had ample shipyard capacity to build the hundreds needed. However, the United States demanded that Germany respect the international agreements upon " freedom of the seas", which protected neutral American ships on the high seas from seizure or sinking by either belligerent. Furthermore, Americans insisted that the drowning of innocent civilians was barbaric and grounds for a declaration of war. The British frequently violated America's neutral rights by seizing ships.  Wilson's top advisor, Colonel Edward M. House commented that, "The British have gone as far as they possibly could in violating neutral rights, though they have done it in the most courteous way".  When Wilson protested British violations of American neutrality, the British backed down.
German submarines torpedoed ships without warning, causing sailors and passengers to drown. Berlin explained that submarines were so vulnerable that they dared not surface near merchant ships that might be carrying guns and which were too small to rescue submarine crews. Britain armed most of its merchant ships with medium calibre guns that could sink a submarine, making above-water attacks too risky. In February 1915, the United States warned Germany about misuse of submarines. On April 22, the German Imperial Embassy warned U.S. citizens against boarding vessels to Britain, which would have to face German attack. On May 7, Germany torpedoed the British passenger liner RMS Lusitania, sinking her. This act of aggression caused the loss of 1,198 civilian lives, including 128 Americans. The sinking of a large, unarmed passenger ship, combined with the previous stories of atrocities in Belgium, shocked Americans and turned public opinion hostile to Germany, although not yet to the point of war. Wilson issued a warning to Germany that it would face "strict accountability" if it sank more neutral U.S. passenger ships.  Berlin acquiesced, ordering its submarines to avoid passenger ships.
By January 1917, however, Field Marshal Paul von Hindenburg and General Erich Ludendorff decided that an unrestricted submarine blockade was the only way to achieve a decisive victory. They demanded that Kaiser Wilhelm order unrestricted submarine warfare be resumed. Germany knew this decision meant war with the United States, but they gambled that they could win before America's potential strength could be mobilized.  However, they overestimated how many ships they could sink and thus the extent Britain would be weakened. Finally, they did not foresee that convoys could and would be used to defeat their efforts. They believed that the United States was so weak militarily that it could not be a factor on the Western Front for more than a year. The civilian government in Berlin objected, but the Kaiser sided with his military. 
The beginning of war in Europe coincided with the end of the Recession of 1913–1914 in America. Exports to belligerent nations rose rapidly over the first four years of the War from $824.8 million in 1913 to $2.25 billion in 1917.  Loans from American financial institutions to the Allied nations in Europe also increased dramatically over the same period.  Economic activity towards the end of this period boomed as government resources aided the production of the private sector. Between 1914 and 1917, industrial production increased 32% and GNP increased by almost 20%.  The improvements to industrial production in the United States outlasted the war. The capital build-up that had allowed American companies to supply belligerents and the American army resulted in a greater long-run rate of production even after the war had ended in 1918. 
In 1913, J. P. Morgan, Jr. took over the House of Morgan, an American-based investment bank consisting of separate banking operations in New York, London, and Paris, after the death of his father, J. Pierpont Morgan.  The House of Morgan offered assistance in the wartime financing of Britain and France from the earliest stages of the war in 1914 through America's entrance in 1917. J.P. Morgan & Co., the House of Morgan's bank in New York, was designated as the primary financial agent to the British government in 1914 after successful lobbying by the British ambassador, Sir Cecil Spring Rice.  The same bank would later take a similar role in France and would offer extensive financial assistance to both warring nations. J.P. Morgan &Co. became the primary issuer of loans to the French government by raising money from American investors.  Morgan, Harjes, the House of Morgan's French affiliated bank, controlled the majority of the wartime financial dealings between the House of Morgan and the French government after primary issuances of debt in American markets.  Relations between the House of Morgan and the French government became tense as the war raged on with no end in sight.  France's ability to borrow from other sources diminished, leading to greater lending rates and a depressing of the value of the franc. After the war, in 1918, J.P. Morgan & Co. continued to aid the French government financially through monetary stabilization and debt relief. 
Because America was still a declared neutral state, the financial dealings of American banks in Europe caused a great deal of contention between Wall Street and the U.S. government. Secretary of State William Jennings Bryan strictly opposed financial support of warring nations and wanted to ban loans to the belligerents in August 1914.  He told President Wilson that "refusal to loan to any belligerent would naturally tend to hasten a conclusion of the war." Wilson at first agreed, but then reversed himself when France argued that if it was legal to buy American goods then it was legal to take out credits on the purchase. 
J.P. Morgan issued loans to France including one in March 1915 and, following negotiations with the Anglo-French Financial Commission, another joint loan to Britain and France in October 1915, the latter amounting to US$500,000,000.  Although the stance of the U.S. government was that stopping such financial assistance could hasten the end of the war and therefore save lives, little was done to insure adherence to the ban on loans, in part due to pressure from Allied governments and American business interests. 
The American steel industry had faced difficulties and declining profits during the Recession of 1913–1914.  As war began in Europe, however, the increased demand for tools of war began a period of heightened productivity that alleviated many U.S. industrial companies from the low-growth environment of the recession. Bethlehem Steel took particular advantage of the increased demand for armaments abroad. Prior to American entrance into the War, these companies benefitted from unrestricted commerce with sovereign customers abroad. After President Wilson issued his declaration of war, the companies were subjected to price controls created by the U.S. Trade Commission in order to insure that the U.S. military would have access to the necessary armaments. 
By the end of the war in 1918, Bethlehem Steel had produced 65,000 pounds of forged military products and 70 million pounds of armor plate, 1.1 billion pounds of steel for shells, and 20.1 million rounds of artillery ammunition for Britain and France.  Bethlehem Steel took advantage of the domestic armaments market and produced 60% of the American weaponry and 40% of the artillery shells used in the War.  Even with price controls and a lower profit margin on manufactured goods, the profits resulting from wartime sales expanded the company into the third largest manufacturing company in the country. Bethlehem Steel became the primary arms supplier for the United States and other allied powers again in 1939. 
Historians divide the views of American political and social leaders into four distinct groupings—the camps were mostly informal:
The first of these were the Non-Interventionists, a loosely affiliated and politically diverse anti-war movement which sought to keep the United States out of the war altogether. Members of this group tended to view the war as a clash between British imperialism and German militarism, both of which they regarded as equally corrupt. Others were pacifists, who objected on moral grounds. Prominent leaders included Democrats like former Secretary of State William Jennings Bryan, industrialist Henry Ford and publisher William Randolph Hearst; Republicans Robert M. La Follette, Senator from Wisconsin and George W. Norris, Senator from Nebraska; and Progressive Party activist Jane Addams.
At the far-left end of the political spectrum the Socialists, led by their perennial candidate for President Eugene V. Debs and movement veterans like Victor L. Berger and Morris Hillquit, were staunch anti-militarists and opposed to any US intervention, branding the conflict as a "capitalist war" that American workers should avoid. However, after the US did join the war in April, 1917 a schism developed between the anti-war Party majority and a pro-war faction of Socialist writers, journalists and intellectuals led by John Spargo, William English Walling and E. Haldeman-Julius. This group founded the rival Social Democratic League of America to promote the war effort among their fellow Socialists. 
Next were the more moderate Liberal-Internationalists. This bipartisan group reluctantly supported a declaration of war against Germany with the postwar goal of establishing collective international security institutions designed to peacefully resolve future conflicts between nations and to promote liberal democratic values more broadly. This groups's views were advocated by interest groups such as the League to Enforce Peace. Adherents included US President Woodrow Wilson, his influential advisor Edward M. House, former President William Howard Taft, famed inventor Alexander Graham Bell, Wall Street financier Bernard Baruch and Harvard University President Abbott Lawrence Lowell. 
Finally, there were the so-called Atlanticists. Ardently pro- Entente, they had strongly championed American intervention in the war since 1915. Their primary political motivation was to both prepare the US for war with Germany and to forge an enduring military alliance with Great Britain. This group actively supported the Preparedness Movement and was strong among the Anglophile political establishment of the northeast, boasting such luminaries as former President Theodore Roosevelt, Major General Leonard Wood, prominent attorney and diplomat Joseph Hodges Choate, former Secretary of War Henry Stimson, journalist Walter Lippman and Senators Henry Cabot Lodge, Sr. of Massachusetts and Elihu Root of New York. 
A cosmopolitan group of upper and upper-middle class businessmen based in the largest cities took the lead in promoting military preparedness and in defining how far America could be pushed around before it would fight back. Many public figures hated war—Secretary of State William Jennings Bryan was the most prominent, and he resigned when he thought Wilson had become too bellicose.  Grassroots opposition to American entry came especially from German and Irish elements.  
A surprising factor in the development of American public opinion was how little the political parties became involved. Wilson and the Democrats in 1916 campaigned on the slogan "He kept us out of war!", saying a Republican victory would mean war with both Mexico and Germany. His position probably was critical in winning the Western states.  Charles Evans Hughes, the GOP candidate, insisted on downplaying the war issue. 
The Socialist party talked peace. Socialist rhetoric declared the European conflict to be "an imperialist war". It won 2% of the 1916 vote for Eugene V. Debs, blamed the war on capitalism and pledged total opposition. "A bayonet", its propaganda said, "was a weapon with a worker at each end".  When war began, however, about half the Socialists, typified by Congressman Meyer London, supported the decision and sided with the pro-Allied efforts. The rest, led by Debs, remained ideological and die-hard opponents.  Many socialists came under investigation from the Espionage Act of 1917 and many suspected of treason were arrested, including Debs. This would only increase the Socialist's anti-war groups in resentment toward the American government. 
The working class was relatively quiet, and tended to divide along ethnic lines. At the beginning of the war, neither working men nor farmers took a large interest in the debates on war preparation.    Samuel Gompers, head of the AFL labor movement, denounced the war in 1914 as "unnatural, unjustified, and unholy", but by 1916 he was supporting Wilson's limited preparedness program, against the objections of Socialist union activists. In 1916 the labor unions supported Wilson on domestic issues and ignored the war question. 
The war at first disrupted the cotton market; Britain blockaded shipments to Germany, and prices fell from 11 cents a pound to only 4 cents. By 1916, however, the British decided to bolster the price to 10 cents to avoid losing Southern support. The cotton growers seem to have moved from neutrality to intervention at about the same pace as the rest of the nation.   Midwestern farmers generally opposed the war, especially those of German and Scandinavian descent. The Midwest became the stronghold of isolationism; other remote rural areas also saw no need for war. 
The African-American community did not take a strong position one way or the other. A month after congress declared war, W. E. B. Du Bois called on African-Americans to "fight shoulder to shoulder with the world to gain a world where war shall be no more".  Once war began and black men were drafted, they worked to achieve equality.  Many had hoped the community's help in the war efforts abroad would earn civil rights at home. When such civil liberties were still not granted, many African-Americans grew tired of waiting for recognition of their rights as American citizens. 
There was a strong antiwar element in the white South and border states. In rural Missouri for example, distrust of powerful Eastern influences focused on the risk that Wall Street would lead America into war.  Across the South poor white farmers warned each other that "a rich man's war meant a poor man's fight," and they wanted nothing of it.  Congressman James Hay, Democrat of Virginia was the powerful chairman of the House Committee on Military Affairs. He repeatedly blocked prewar efforts to modernize and enlarge the army. Preparedness was not needed because Americans were already safe, he insisted in January 1915:
- Isolated as we are, safe in our vastness, protected by a great navy, and possessed of an army sufficient for any emergency that may arise, we may disregard the lamentations and predictions of the militarists. 
German Americans by this time usually had only weak ties to Germany; however, they were fearful of negative treatment they might receive if the United States entered the war (such mistreatment was already happening to German-descent citizens in Canada and Australia). Almost none called for intervening on Germany's side, instead calling for neutrality and speaking of the superiority of German culture. As more nations were drawn into the conflict, however, the English-languages press increasingly supporting Britain, while the German-American media called for neutrality while also defending Germany's position. Chicago's Germans worked to secure a complete embargo on all arms shipments to Europe. In 1916, large crowds in Chicago's Germania celebrated the Kaiser's birthday, something they had not done before the war.  German Americans in early 1917 still called for neutrality, but proclaimed that if a war came they would be loyal to the United States. By this point, they had been excluded almost entirely from national discourse on the subject.  Once war started, they were harassed in so many ways that historian Carl Wittke noted in 1936, it was "one of the most difficult and humiliating experiences suffered by an ethnic group in American history."  German-American Socialists in Milwaukee, Wisconsin actively campaigned against entry into the war. 
Leaders of most religious groups (except the Episcopalians) tended to pacifism, as did leaders of the woman's movement. The Methodists and Quakers among others were vocal opponents of the war.  President Wilson, who was a devout Presbyterian, would often frame the war in terms of good and evil in an appeal for religious support of the war. 
A concerted effort was made by pacifists including Jane Addams, Oswald Garrison Villard, David Starr Jordan, Henry Ford, Lillian Wald, and Carrie Chapman Catt. Their goal was to encourage Wilson's efforts to mediate an end of the war by bringing the belligerents to the conference table.  Finally in 1917 Wilson convinced some of them that to be truly anti-war they needed to support what he promised would be "a war to end all wars". 
Once war was declared, the more liberal denominations, which had endorsed the Social Gospel, called for a war for righteousness that would help uplift all mankind. The theme—an aspect of American exceptionalism—was that God had chosen America as his tool to bring redemption to the world. 
American Catholic bishops maintained a general silence toward the issue of intervention. Millions of Catholics lived in both warring camps, and Catholic Americans tended to split on ethnic lines in their opinions toward American involvement in the war. At the time, heavily Catholic towns and cities in the East and Midwest often contained multiple parishes, each serving a single ethnic group, such as Irish, German, Italian, Polish, or English. American Catholics of Irish and German descent opposed intervention most strongly. Pope Benedict XV made several attempts to negotiate a peace. All of his efforts were rebuffed by both the Allies and the Germans, and throughout the war the Vatican maintained a policy of strict neutrality.
Jewish American sympathies likewise broke along ethnic lines, with recently arrived Yiddish speaking Jews inclined to Zionism, and the established German-American Jewish community largely opposed to it. In 1914–1916, there were few Jewish forces in favor of American entry into the war. Many regarded Britain as hostile to Jewish interests. New York City, with its well-organized element numbering 1.5 million Jews, was the center of antiwar activism.  
Of greatest concern to Jews was the tsarist regime in Russia because it was notorious for tolerating pogroms and following anti-Semitic policies. As historian Joseph Rappaport reported through his study of Yiddish press during the war, "The pro-Germanism of America's immigrant Jews was an inevitable consequence of their Russophobia".  The fall of the tsarist regime in March 1917 removed a major obstacle for many Jews who refused to support tsarism.  The draft went smoothly in New York City, and left-wing opposition to the war largely collapsed when Zionists saw the possibility of using the war to demand a state of Israel. 
The most effective domestic opponents of the war were Irish-American Catholics. They had little interest in the continent, but were neutral about helping the United Kingdom because it had recently enacted the Government of Ireland Act 1914, allowing Irish Home Rule. However, the Act was suspended until the war ended. John Redmond and the Irish Parliamentary Party (IPP) declared that Irish Volunteers should support America's pro-Allied war efforts first; his political opponents argued that it was not the time to support Britain in its attempt to "strengthen and expand her empire".  The attacks on the IPP and pro-Allied press showed a firm belief that a German victory would hasten the achievement of Irish independence. Yet rather than proposing intervention on behalf of the Germans, Irish American leaders and organizations focused on demanding American neutrality. But the increased contact between militant Irish nationalists and German agents in the United States only fueled concerns of where the primary loyalties of Irish Americans lay.  Nevertheless, close to 1,000 Irish-born Americans died fighting with the U.S. armed forces in WWI. 
The Easter Rising in Dublin in April 1916 was crushed within a week and its leaders executed by firing squad. The mainstream American press treated the uprising as foolish and misguided, and theorized it was largely inspired by the Germans. Overall public opinion remained faithfully pro-British. 
Irish-Americans dominated the Democratic party in many large cities so Wilson had to take account of their views. They did not prevent him from being hostile to Germany, but they did force him to keep his distance from Britain. Indeed, Irish-American pressure influenced the United States into not accepting Britain's war aims as its own and define its own objectives, primarily self-determination. The Irish-American community thought they had Wilson's promise to promote Irish independence in exchange for their support of his war policies, but after the war they were bitterly disappointed by his refusal to support them in 1919.  Wilson saw the Irish situation purely as an internal UK matter and did not perceive the dispute and the unrest in Ireland as comparable to the plight of the various nationalities in Europe as a fall-out from World War I.  The progress of the Irish Race Conventions give a flavour of the differing and changing opinions during the war.
Some British immigrants worked actively for intervention. London-born Samuel Insull, Chicago's leading industrialist, for example, enthusiastically provided money, propaganda, and means for volunteers to enter the British or Canadian armies. After the United States' entry, Insull directed the Illinois State Council of Defense, with responsibility for organizing the state's mobilization. 
Immigrants from eastern Europe usually cared more about politics in their homeland than politics in the United States. Spokesmen for Slavic immigrants hoped that an Allied victory would bring independence for their homelands.  Large numbers of Hungarian immigrants who were liberal and nationalist in sentiment, and sought an independent Hungary, separate from the Austro-Hungarian Empire lobbied in favor of the war and allied themselves with the Atlanticist or Anglophile portion of the population. This community was largely pro-British and anti-German in sentiment.    Albanian-Americans in communities such as Boston also campaigned for entry into the war and were overwhelmingly pro-British and anti-German, as well as hopeful the war would lead to an independent Albania which would be free from the Ottoman Empire.  Polish, Slovak, and Czech immigrants were enthusiastically pro-war and generally pro-British.
Henry Ford supported the pacifist cause by sponsoring a large-scale private peace mission, with numerous activists and intellectuals aboard the " Peace Ship' (the ocean liner Oscar II). Ford chartered the ship in 1915 and invited prominent peace activists to join him to meet with leaders on both sides in Europe. He hoped to create enough publicity to prompt the belligerent nations to convene a peace conference and mediate an end to the war. The mission was widely mocked by the press, which wrote about the "Ship of Fools." Infighting between the activists, mockery by the press contingent aboard, and an outbreak of influenza marred the voyage. Four days after the ship arrived in neutral Norway, a beleaguered and physically ill Ford abandoned the mission and returned to the United States; he had demonstrated that independent small efforts accomplished nothing. 
On July 24, 1915, the German embassy's commercial attaché, Heinrich Albert, left his briefcase on a train in New York City, where an alert Secret Service agent, Frank Burke, snatched it up.  Wilson let the newspapers publish the contents, which indicated a systematic effort by Berlin to subsidize friendly newspapers and block British purchases of war materials. Berlin's top espionage agent, debonnaire Franz Rintelen von Kleist was spending millions to finance sabotage in Canada, stir up trouble between the United States and Mexico and to incite labor strikes. The British were engaged in propaganda too, though not illegal espionage, but they did not get caught.  Germany took the blame as Americans grew ever more worried about the vulnerability of a free society to subversion. Indeed, one of the main fears Americans of all stations had in 1916–1919 was that spies and saboteurs were everywhere. This sentiment played a major role in arousing fear of Germany, and suspicions regarding everyone of German descent who could not "prove" 100% loyalty. 
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By 1915, Americans were paying much more attention to the war. The sinking of the Lusitania had a strong effect on public opinion because of the deaths of American civilians. That year, a strong "Preparedness" movement emerged.  Proponents argued that the United States needed to immediately build up strong naval and land forces for defensive purposes; an unspoken assumption was that America would fight sooner or later. General Leonard Wood (still on active duty after serving a term as Chief of Staff of the Army), former president Theodore Roosevelt, and former secretaries of war Elihu Root and Henry Stimson were the driving forces behind Preparedness, along with many of the nation's most prominent bankers, industrialists, lawyers and scions of prominent families. Indeed, there emerged an "Atlanticist" foreign policy establishment, a group of influential Americans drawn primarily from upper-class lawyers, bankers, academics, and politicians of the Northeast, committed to a strand of Anglophile internationalism. Representative was Paul D. Cravath, one of New York's foremost corporation lawyers. For Cravath, in his mid-fifties when the war began, the conflict served as an epiphany, sparking an interest in international affairs that dominated his remaining career. Fiercely Anglophile, he strongly supported American intervention in the war and hoped that close Anglo-American cooperation would be the guiding principle of postwar international organization. 
The Preparedness movement had a "realistic" philosophy of world affairs—they believed that economic strength and military muscle were more decisive than idealistic crusades focused on causes like democracy and national self-determination. Emphasizing over and over the weak state of national defenses, they showed that America's 100,000-man Army even augmented by the 112,000 National Guardsmen, was outnumbered 20 to one by Germany's army, which was drawn from a smaller population. Similarly in 1915, the armed forces of Great Britain and the British empire (the world's most powerful military and economic power at the time ), France, Russia, the Austro-Hungarian empire, Ottoman empire, Italy, Bulgaria, Romania, Serbia, Belgium, Japan and Greece were all larger and more experienced than the United States military, in many cases significantly so. 
Reform to them meant UMT or "universal military training". They proposed a national service program under which the 600,000 men who turned 18 every year would be required to spend six months in military training, and afterwards be assigned to reserve units. The small regular army would primarily be a training agency.
Antimilitarists complained the plan would make America resemble Germany (which required two years' active duty). Advocates retorted that military "service" was an essential duty of citizenship, and that without the commonality provided by such service the nation would splinter into antagonistic ethnic groups. One spokesman promised that UMT would become "a real melting pot, under which the fire is hot enough to fuse the elements into one common mass of Americanism". Furthermore, they promised, the discipline and training would make for a better paid work force. Hostility to military service was strong at the time, and the program failed to win approval. In World War II, when Stimson as Secretary of War proposed a similar program of universal peacetime service, he was defeated. 
Underscoring its commitment, the Preparedness movement set up and funded its own summer training camps at Plattsburgh, New York, and other sites, where 40,000 college alumni became physically fit, learned to march and shoot, and ultimately provided the cadre of a wartime officer corps.  Suggestions by labor unions that talented working-class youth be invited to Plattsburgh were ignored. The Preparedness movement was distant not only from the working classes but also from the middle-class leadership of most of small-town America. It had had little use for the National Guard, which it saw as politicized, localistic, poorly armed, ill trained, too inclined to idealistic crusading (as against Spain in 1898), and too lacking in understanding of world affairs. The National Guard on the other hand was securely rooted in state and local politics, with representation from a very broad cross section of American society. The Guard was one of the nation's few institutions that (in some northern states) accepted blacks on an equal footing.
The Democratic party saw the Preparedness movement as a threat. Roosevelt, Root and Wood were prospective Republican presidential candidates. More subtly, the Democrats were rooted in localism that appreciated the National Guard, and the voters were hostile to the rich and powerful in the first place. Working with the Democrats who controlled Congress, Wilson was able to sidetrack the Preparedness forces. Army and Navy leaders were forced to testify before Congress to the effect that the nation's military was in excellent shape.
In fact, neither the Army nor Navy was in shape for war. The Navy had fine ships but Wilson had been using them to threaten Mexico, and the fleet's readiness had suffered. The crews of the Texas and the New York, the two newest and largest battleships, had never fired a gun, and the morale of the sailors was low. In addition, it was outnumbered and outgunned by the British, German, French, and Italian navies. The Army and Navy air forces were tiny in size. Despite the flood of new weapons systems unveiled by the British, Germans, French, Austro-Hungarians, Italians, and others in the war in Europe, the Army was paying scant attention. For example, it was making no studies of trench warfare, poison gas, heavy artillery, or tanks and was utterly unfamiliar with the rapid evolution of Aerial warfare. The Democrats in Congress tried to cut the military budget in 1915. The Preparedness movement effectively exploited the surge of outrage over the Lusitania in May 1915, forcing the Democrats to promise some improvements to the military and naval forces. Wilson, less fearful of the Navy, embraced a long-term building program designed to make the fleet the equal of the British Royal Navy by the mid-1920s, although this would not be achieved until World War II. "Realism" was at work here; the admirals were Mahanians and they therefore wanted a surface fleet of heavy battleships second to none—that is, equal to Britain. The facts of submarine warfare (which necessitated destroyers, not battleships) and the possibilities of imminent war with Germany (or with Britain, for that matter), were simply ignored.
Wilson's program for the Army touched off a firestorm.  Secretary of War Lindley Garrison adopted many of the proposals of the Preparedness leaders, especially their emphasis on a large federal reserve and abandonment of the National Guard. Garrison's proposals not only outraged the localistic politicians of both parties, they also offended a strongly held belief shared by the liberal wing of the Progressive movement. They felt that warfare always had a hidden economic motivation. Specifically, they warned the chief warmongers were New York bankers (like J. P. Morgan) with millions at risk, profiteering munition makers (like Bethlehem Steel, which made armor, and DuPont, which made powder) and unspecified industrialists searching for global markets to control. Antiwar critics blasted them. These special interests were too powerful, especially, Senator La Follette noted, in the conservative wing of the Republican Party. The only road to peace was disarmament, reiterated Bryan.
Garrison's plan unleashed the fiercest battle in peacetime history over the relationship of military planning to national goals. In peacetime, War Department arsenals and Navy yards manufactured nearly all munitions that lacked civilian uses, including warships, artillery, naval guns, and shells. Items available on the civilian market, such as food, horses, saddles, wagons, and uniforms were always purchased from civilian contractors. Armor plate (and after 1918, airplanes) was an exception that has caused unremitting controversy for a century. After World War II, the arsenals and Navy yards were much less important than giant civilian aircraft and electronics firms, which became the second half of the " military-industrial complex" Peace leaders like Jane Addams of Hull House and David Starr Jordan of Stanford redoubled their efforts, and now turned their voices against the president because he was "sowing the seeds of militarism, raising up a military and naval caste". Many ministers, professors, farm spokesmen, and labor union leaders joined in, with powerful support from a band of four dozen southern Democrats in Congress who took control of the House Military Affairs Committee. Wilson, in deep trouble, took his cause to the people in a major speaking tour in early 1916, a warmup for his reelection campaign that fall. Wilson seems to have won over the middle classes, but had little impact on the largely ethnic working classes and the deeply isolationist farmers. Congress still refused to budge, so Wilson replaced Garrison as Secretary of War with Newton Baker, the Democratic mayor of Cleveland and an outspoken opponent of preparedness (Garrison kept quiet, but felt Wilson was "a man of high ideals but no principles"). The upshot was a compromise passed in May 1916, as the war raged on and Berlin was debating whether America was so weak it could be ignored. The Army was to double in size to 11,300 officers and 208,000 men, with no reserve, and a National Guard that would be enlarged in five years to 440,000 men. Summer camps on the Plattsburg model were authorized for new officers, and the government was given $20 million to build a nitrate plant of its own. Preparedness supporters were downcast, the antiwar people were jubilant. America would now be too weak to go to war. Colonel Robert L. Bullard privately complained that "Both sides [Britain and Germany] treat us with scorn and contempt; our fool, smug conceit of superiority has been exploded in our faces and deservedly." The House gutted the naval plans as well, defeating a "big navy" plan by 189 to 183, and scuttling the battleships. The battle of Jutland (May 31/June 1, 1916) was used by the navalists to argue for the primacy of seapower; they then took control in the Senate, broke the House coalition, and authorized a rapid three-year buildup of all classes of warships. A new weapons system, naval aviation, received $3.5 million, and the government was authorized to build its own armor plate factory. The very weakness of American military power encouraged Berlin to start its unrestricted submarine attacks in 1917. It knew this meant war with America, but it could discount the immediate risk because the U.S. Army was negligible and the new warships would not be at sea until 1919 by which time the war would be over, with Germany victorious. The notion that armaments led to war was turned on its head: refusal to arm in 1916 led to war in 1917.
Americans felt an increasing need for a military that could command respect. As one editor put it, "The best thing about a large army and a strong navy is that they make it so much easier to say just what we want to say in our diplomatic correspondence." Berlin thus far had backed down and apologized when Washington was angry, thus boosting American self-confidence. America's rights and America's honor increasingly came into focus. The slogan "Peace" gave way to "Peace with Honor". The Army remained unpopular, however. A recruiter in Indianapolis noted that, "The people here do not take the right attitude towards army life as a career, and if a man joins from here he often tries to go out on the quiet". The Preparedness movement used its easy access to the mass media to demonstrate that the War Department had no plans, no equipment, little training, no reserve, a laughable National Guard, and a wholly inadequate organization for war. Motion pictures like The Battle Cry of Peace (1915) depicted invasions of the American homeland that demanded action. 
The readiness and capability of the U.S. Navy was a matter of controversy. The press at the time reported that the only thing the military was ready for was an enemy fleet attempting to seize New York harbor—at a time when the German battle fleet was penned up by the Royal Navy. The Navy Secretary Josephus Daniels was a journalist with pacifist leanings.  He had built up the educational resources of the Navy and made its Naval War College in Newport, Rhode Island an essential experience for would-be admirals. However, he alienated the officer corps with his moralistic reforms, including no wine in the officers' mess, no hazing at the Naval Academy, and more chaplains and YMCAs. Daniels, as a newspaperman, knew the value of publicity. In 1915 he set up the Naval Consulting Board headed by Thomas Edison to obtain the advice and expertise of leading scientists, engineers, and industrialists. It popularized technology, naval expansion, and military preparedness, and was well covered in the media.  But according to Coletta he ignored the nation's strategic needs, and disdaining the advice of its experts, Daniels suspended meetings of the Joint Army and Navy Board for two years because it was giving unwelcome advice, chopped in half the General Board's recommendations for new ships, reduced the authority of officers in the Navy yards where ships were built and repaired, and ignored the administrative chaos in his department. Bradley Fiske, one of the most innovative admirals in American naval history, in 1914 was Daniels' top aide; he recommended a reorganization that would prepare for war, but Daniels refused. Instead he replaced Fiske in 1915 and brought in for the new post of Chief of Naval Operations an unknown captain, William Benson. Chosen for his compliance, Benson proved a wily bureaucrat who was more interested in preparing for an eventual showdown with Britain than an immediate one with Germany. Benson told Sims he "would as soon fight the British as the Germans". Proposals to send observers to Europe were blocked, leaving the Navy in the dark about the success of the German submarine campaign. Admiral William Sims charged after the war that in April 1917, only ten percent of the Navy's warships were fully manned; the rest lacked 43% of their seamen. Light antisubmarine ships were few in number, as if Daniels had been unaware of the German submarine menace that had been the focus of foreign policy for two years. The Navy's only warfighting plan, the "Black Plan" assumed the Royal Navy did not exist and that German battleships were moving freely about the Atlantic and the Caribbean and threatening the Panama Canal. Daniels' tenure would have been even less successful save for the energetic efforts of Assistant Secretary Franklin D. Roosevelt, who effectively ran the Department.  His most recent biographer concludes that, "it is true that Daniels had not prepared the navy for the war it would have to fight." 
By 1916 a new factor was emerging—a sense of national self-interest and American nationalism. The unbelievable casualty figures in Europe were sobering—two vast battles caused over one million casualties each. Clearly this war would be a decisive episode in the history of the world. Every American effort to find a peaceful solution was frustrated.
Kendrick Clements claims bureaucratic decision-making was one of the main sources pushing the United States to declaring war on Germany and aligning itself with the Allies. He cites the State Department's demand that Germany's submarines obey outdated, 18th century sailing laws as one of the first missteps by the United States bureaucracy regarding the war. By doing so, the United States had essentially given Germany the choice of whether or not the U.S. would enter the war. Secretary of State William Jennings Bryan spent most of the fall of 1914 out of contact with the State Department, leaving the more conservative Robert Lansing with the ability to shape American foreign policy at the time. One of these decisions was made in response to British protests that the Germans were using U.S. radio towers to send messages to their warships. Immediately prior to the war starting in 1914, Britain had cut all cable communications leading out of Germany, including the trans-Atlantic cable. The US Government permitted German embassies to use the US cable lines for "proper" diplomatic business. Germany argued that usage of the towers was necessary to allow efficient contact between the U.S. and Germany. Lansing responded by requiring both sides to give the U.S. Navy copies of the messages they sent over the towers. The French and British were still able to use the cables, forcing Germany to be the only belligerent required to provide the U.S. with their messages. This and other seemingly small decisions made by Lansing during this time would eventually stack up, shifting American support towards the Allies. 
Once Germany had decided on unrestricted submarine warfare in January 1917, and knowing it would be attacking all American ships in the North Atlantic, it tried to line up new allies, especially Mexico. Arthur Zimmermann, the German foreign minister, sent the Zimmermann Telegram to Mexico on January 16, 1917. Zimmermann invited Mexico (knowing their resentment towards America since the 1848 Mexican Cession) to join in a war against the United States. Germany promised to pay for Mexico's costs and to help it recover the territory annexed by the U.S. in 1848. These territories included the present day states of California, Nevada, Utah, most of Arizona, about half of New Mexico and a quarter of Colorado. British intelligence intercepted and decoded the telegram and passed it to the Wilson administration. The White House would release it to the press on March 1. Anger grew further as the Germans began sinking American ships, even as isolationists in the Senate launched a filibuster to block legislation for arming American merchant ships to defend themselves.  
In early 1917 Berlin forced the issue. Its declared decision on 31 January 1917 to target neutral shipping in a designated war-zone  became the immediate cause of the entry of the United States into the war.  Five American merchant ships went down in March. Outraged public opinion now overwhelmingly supported Wilson when he asked Congress for a declaration of war on April 2, 1917. 
Historians such as Ernest R. May have approached the process of American entry into the war as a study in how public opinion changed radically in three years' time. In 1914 most Americans called for neutrality, seeing the war a dreadful mistake and were determined to stay out. By 1917 the same public felt just as strongly that going to war was both necessary and wise. Military leaders had little to say during this debate, and military considerations were seldom raised. The decisive questions dealt with morality and visions of the future. The prevailing attitude was that America possessed a superior moral position as the only great nation devoted to the principles of freedom and democracy. By staying aloof from the squabbles of reactionary empires, it could preserve those ideals—sooner or later the rest of the world would come to appreciate and adopt them. In 1917 this very long-run program faced the severe danger that in the short run powerful forces adverse to democracy and freedom would triumph. Strong support for moralism came from religious leaders, women (led by Jane Addams), and from public figures like long-time Democratic leader William Jennings Bryan, the Secretary of State from 1913 to 1916. The most important moralist of all was President Woodrow Wilson—the man who dominated decision making so totally that the war has been labelled, from an American perspective, "Wilson's War". 
In 1917 Wilson won the support of most of the moralists by proclaiming "a war to make the world safe for democracy." If they truly believed in their ideals, he explained, now was the time to fight. The question then became whether Americans would fight for what they deeply believed in, and the answer turned out to be a resounding "Yes". 
Antiwar activists at the time and in the 1930s, alleged that beneath the veneer of moralism and idealism there must have been ulterior motives. Some suggested a conspiracy on the part of New York City bankers holding $3 billion of war loans to the Allies, or steel and chemical firms selling munitions to the Allies.  The interpretation was popular among left-wing Progressives (led by Senator Robert La Follette of Wisconsin) and among the "agrarian" wing of the Democratic party—including the chairman of the tax-writing Ways and Means Committee of the House. He strenuously opposed war, and when it came he rewrote the tax laws to make sure the rich paid the most. (In the 1930s neutrality laws were passed to prevent financial entanglements from dragging the nation into a war.) In 1915, Bryan thought that Wilson's pro-British sentiments had distorted his policies, so he became the first Secretary of State ever to resign in protest. 
However, historian Harold C. Syrett argues that business supported neutrality.  Other historians state that the pro-war element was animated not by profit but by disgust with what Germany actually did, especially in Belgium, and the threat it represented to American ideals. Belgium kept the public's sympathy as the Germans executed civilians,  and English nurse Edith Cavell. American engineer Herbert Hoover led a private relief effort that won wide support. Compounding the Belgium atrocities were new weapons that Americans found repugnant, like poison gas and the aerial bombardment of innocent civilians as Zeppelins dropped bombs on London.  Even anti-war spokesmen did not claim that Germany was innocent, and pro-German scripts were poorly received. 
Randolph Bourne criticized the moralist philosophy claiming it was a justification by American intellectual and power elites, like President Wilson, for going to war unnecessarily. He argues that the push for war started with the Preparedness movement, fueled by big business. While big business would not push much further than Preparedness, benefitting the most from neutrality, the movement would eventually evolve into a war-cry, led by war-hawk intellectuals under the guise of moralism. Bourne believes elites knew full well what going to war would entail and the price in American lives it would cost. If American elites could portray the United States' role in the war as noble, they could convince the generally isolationist American public war would be acceptable. 
Above all, American attitudes towards Germany focused on the U-boats (submarines), which sank the Lusitania in 1915 and other passenger ships "without warning".    That appeared to Americans as an unacceptable challenge to America's rights as a neutral country, and as an unforgivable affront to humanity. After repeated diplomatic protests, Germany agreed to stop. But in 1917 the Germany military leadership decided that "military necessity" dictated the unrestricted use of their submarines. The Kaiser's advisors felt America was enormously powerful economically but too weak militarily to make a difference.
On April 2, 1917, Wilson asked a special joint session of Congress to declare war on the German Empire, stating, "We have no selfish ends to serve".  To make the conflict seem like a better idea, he painted the conflict idealistically, stating that the war would "make the world safe for democracy" and later that it would be a "war to end war". The United States had a moral responsibility to enter the war, Wilson proclaimed. The future of the world was being determined on the battlefield, and American national interest demanded a voice. Wilson's definition of the situation won wide acclaim, and, indeed, has shaped America's role in world and military affairs ever since. Wilson believed that if the Central Powers won, the consequences would be bad for the United States. Germany would have dominated the continent and perhaps would gain control of the seas as well. Latin America could well have fallen under Berlin's control. The dream of spreading democracy, liberalism, and independence would have been shattered. On the other hand, if the Allies had won without help, there was a danger they would carve up the world without regard to American commercial interests. They were already planning to use government subsidies, tariff walls, and controlled markets to counter the competition posed by American businessmen. The solution was a third route, a "peace without victory", according to Wilson. 
On April 6, 1917, Congress declared war. In the Senate, the resolution passed 82 to 6, with Senators Harry Lane, William J. Stone, James Vardaman, Asle Gronna, Robert M. La Follette, Sr., and George W. Norris voting against it. In the House, the declaration passed 373 to 50, with Claude Kitchin, a senior Democrat, notably opposing it. Another opponent was Jeannette Rankin, who alone voted against entry into both World War I and World War II. Nearly all of the opposition came from the West and the Midwest. 
The United States Senate, in a 74 to 0 vote, declared war on Austria-Hungary on December 7, 1917, citing Austria-Hungary's severing of diplomatic relations with the United States, its use of unrestricted submarine warfare and its alliance with Germany.  The declaration passed in the United States House of Representatives by a vote of 365 to 1. 
President Wilson also came under pressure from Senator Henry Cabot Lodge, and from former President Theodore Roosevelt, who demanded a declaration of war on Ottoman Empire and Bulgaria, as Germany's allies. President Wilson drafted a statement to Congress in December 1917 which said "I... recommend that Congress immediately declare the United States in a state of war with Austria-Hungary, with Turkey and with Bulgaria". But after further consultations decision on war against Germany's other allies was postponed. 
- Causes of World War I
- Diplomatic history of World War I
- United States in World War I
- United States home front during World War I
- Jeanette Keith (2004). Rich Man's War, Poor Man's Fight: Race, Class, and Power in the Rural South during the First World War. U. of North Carolina Press. pp. 1–5. ISBN 978-0-8078-7589-6.
- Barnes, Harry Elmer. The Genesis of the World War (1925) pp. 590–591
- "World War One". BBC History.
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- H.J.Res.169: Declaration of War with Austria-Hungary, WWI, United States Senate
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- Eric W. Osborne, Britain's economic blockade of Germany, 1914–1919 (2004)
- Ernest May, The World War and American Isolation, 1914–1917 (1959) p. 115 quote from Dec 1914.
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- Edward House, The intimate papers of Colonel House: Vol 2 (1928) p. 73
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- Lawrence O. Christensen, "World War I in Missouri," Missouri Historical Review, 90 (1996), 330-354, 410-428.
- Edwin Costrell, How Maine viewed the war, 1914–1917 (1940)
- John C. Crighton, Missouri and the World War, 1914–1917: a study in public opinion (1947)
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- Arthur S. Link, Woodrow Wilson and the Progressive Era (1954) pp. 169–72
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- Mark Ellis, "America's Black Press, 1914–18," History Today, Sept 1991, Vol. 41, Issue 9
- Panikos Panayi, "Minorities in Wartime: National and Racial Groupings in Europe, North America, and Australia During the Two World Wars" (1992) p. 171
- Christopher C. Gibbs, Great Silent Majority: Missouri's Resistance to World War I (1988)
- Jeanette Keith (2004). Rich Man's War, Poor Man's Fight: Race, Class, and Power in the Rural South During the First World War. U. of North Carolina Press. p. 85.
- George C. Herring, "James Hay and the Preparedness Controversy, 1915–1916." Journal of Southern History (1964) 30#4 pp. 383–404 quote, p. 386 in JSTOR
- Leslie V. Tischauser, The Burden of Ethnicity: The German Question in Chicago, 1914–1941 (Garland, 1990) pp. 21–23
- Frederick C. Luebke, Bonds of Loyalty: German-Americans and World War I (1974) pp. 200–207
- Carl Wittke, German-Americans and the World War (with Special Emphasis on Ohio's German-Language Press) (Columbus, Ohio, 1936), p. 209
- See Wisconsin Historical Society, "World War I, at home and in the trenches"
- John F. Piper, The American Churches in World War I (1985).
- Samuel S. Hill, Charles H. Lippy, and Charles Reagan Wilson, Encyclopedia of Religion in the South (2005) p. 297
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- Zosa Szajkowski, Jews, Wars, and Communism. Vol. I: The Attitude of American Jews to World War I, the Russian Revolutions of 1917, and Communism (1914–1945) (New York: KTAV, 1973) includes a great deal of undigested information.
- Joseph Rappaport, Jewish Immigrants and World War I: A Study of Yiddish Attitudes(1951), p. 78
- Henry L. Feingold (2007). "Silent No More": Saving the Jews of Russia, the American Jewish Effort, 1967–1989. Syracuse UP. p. 13.
- Sterba, Good Americans (2003), 68–69, 76, 79, 167-69
- Malcolm Campbell, Ireland's New Worlds, (2008), p. 164
- Malcolm Campbell, Ireland's New Worlds, (2008), p. 174
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- Malcolm Campbell, Ireland's New Worlds, (2008), p. 170
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- Kennedy, Billy. "Woodrow Wilson". Ulstervirginia.com. "Archived copy". Archived from the original on 2007-12-12. Retrieved 2015-02-08. . Retrieved November 10, 2011.
- McDonald, Forrest (2004). Insull: The Rise and Fall of a Billionaire Utility Tycoon. Washington: Beard Books. pp. 162–187. ISBN 1-58798-243-9.
- O'Grady, Joseph (1967). The Immigrants' Influence on Wilson's Peace Policies. Lexington: University of Kentucky Press.
- The Hungarian-Americans by Steven Béla Várdy; Twayne Publishers, 1985 page 87–99
- Christopher M. Sterba, Good Americans: Italian and Jewish Immigrants During the First World War,(2003) p. 31–32
- Michael T. Urbanski, "Money, War, and Recruiting an Army: The Activities of Connecticut Polonia During World War I," Connecticut History (2007) 46#1 pp. 45–69.
- The Albanian-American Odyssey: A Pilot Study of the Albanian Community of Boston, Massachusetts Front Cover Dennis L. Nagi AMS Press, Jan 1, 1989, pp. 33–35
- Mark W. van Wienen (1997). Partisans and Poets: The Political Work of American Poetry in the Great War. Cambridge UP. p. 57.
- Barbara S. Kraft, The Peace Ship: Henry Ford's Pacifist Adventure in the First World War (1978) p. 81
- Max Wallace, The American Axis (New York, New York: St. Martin's Press, 2003), pp. 224–225.
- H.C. Peterson, Propaganda for war: The campaign against American neutrality, 1914–1917 (1968)
- Link 3:556ff
- George C. Herring, "James Hay and the Preparedness Controversy, 1915–1916." Journal of Southern History (1964) 30#4 pp. 383–404 in JSTOR
- Roberts, Priscilla (2005). "Paul D. Cravath, the First World War, and the Anglophile Internationalist Tradition". Australian Journal of Politics and History. 51 (2): 194–215. doi: 10.1111/j.1467-8497.2005.00370.x.
- "World War I facts, information, pictures | Encyclopedia.com articles about World War I". Encyclopedia.com. Retrieved 2016-11-06.
- Scott Manning (2007-01-04). "World War I: Troop Statistics". Scottmanning.com. Retrieved 2016-11-06.
- Chambers 93; Weigley Army 345
- Very few young men from wealthy or prominent families considered a career in the Army or Navy then or at any time in American history. The highest social background of cadets, exemplified by George Patton, West Point 1909, and Lucius Clay, 1918, was oldest son of a locally prominent family.
- Link, Woodrow Wilson, pp. 179ff
- Herring, "James Hay and the Preparedness Controversy, 1915–1916," p. 383
- Paolo Coletta, American Secretaries of the Navy (1980) 2:526-41
- Theodore A. Thelander, "Josephus Daniels and the Publicity Campaign for Naval and Industrial Preparedness before World War I," North Carolina Historical Review (1966) 43#3 pp. 316–332
- Lee A. Craig (2013). Josephus Daniels: His Life and Times. U. North Carolina Press. pp. 364–65.
- Kendrick A. Clements, "Woodrow Wilson and World War I." Presidential Studies Quarterly (2004) 34#1 pp. 62–82.
- Cooper, Woodrow Wilson (2011) pp. 378–79
- Thomas Boghardt, The Zimmermann Telegram: Intelligence, Diplomacy, and America's Entry into World War I (2012) Excerpt and text search, summarized in Thomas Boghardt's The Zimmermann Telegram: Diplomacy, Intelligence and The American Entry into World War I (2003) online
Doenecke, Justus D. (2011).
Nothing Less Than War: A New History of America's Entry Into World War I. Studies in Conflict, Diplomacy and Peace Series. University Press of Kentucky. p. 250.
978-0-8131-3002-6. Retrieved 2015-12-07.
On January 31, Ambassador Bernstorff presented [...] Germany's response to Wilson's recent 'peace without victory' plea [...]: his nation was about to launch an unrestricted submarine campaign, thereby declaring total maritime war against all neutrals. After February 1, the communique noted, German U-boats would sink without warning belligerent and neutral ships found in a designated zone comprising waters around Great Britain, France, and Italy, and in the eastern Mediterranean. The Admiralty made one minor exception: it would permit one American steamer a week to sail between New York and Falmouth [...]. Initially Germany would grant a period of grace, during which its submarines would not harm neutral ships that either were en route to the war zone or had already arrived.
Doenecke, Justus D. (2011).
Nothing Less Than War: A New History of America's Entry Into World War I. Studies in Conflict, Diplomacy and Peace Series. University Press of Kentucky. p. 286.
978-0-8131-3002-6. Retrieved 2015-12-07.
Several factors led to Wilson's choice. Germany's U-boat warfare was paramount. Had it not been for Berlin's announcement of January 31, the president probably would not have issued a call to arms.
- Justus D. Doenecke, Nothing Less Than War: A New History of America's Entry into World War I (2011) ch 10
- May, Ernest R. (1966). The World War and American isolation, 1914–1917.
- Knock, Thomas J. (1995). To End All Wars: Woodrow Wilson and the Quest for a New World Order.
- Syrett, Harold C. (1945). "The Business Press and American Neutrality, 1914–1917". Mississippi Valley Historical Review. 32 (2): 215–230. doi: 10.2307/1898209. JSTOR 1898209.
- Robert W. Cherny, A righteous cause: the life of William Jennings Bryan (1994) p. 144
- Syrett, "The Business Press and American Neutrality, 1914–1917,"
- The German army executed over 6,500 French and Belgian civilians between August and November 1914, usually in near-random large-scale shootings of civilians ordered by junior German officers. Horne, John; Kramer, Alan (2001). German Atrocities, 1914: A History of Denial. New Haven: Yale U.P. ISBN 0-300-08975-9.
- Bonadio, Felice A. (1959). "The Failure of German Propaganda in the United States, 1914–1917". Mid America. 41 (1): 40–57.
- Bourne, Randolph. "The War and the Intellectuals." N.p.: n.p., n.d. 133-46. Print.
- DISASTER BEARS OUT EMBASSY'S WARNING; German Advertisement Practically Foretold Lusitania's Fate on Day She Sailed. AND IS REPEATED TODAY Passengers Also Said to Have Received Telegrams -- Shipping Men Heard of Threats.
- Germany, U-Boats and the Lusitania
- The Lusitania
- for detailed coverage of the speech see NY Times main headline, April 2, 1917, President Calls for War Declaration, Stronger Navy, New Army of 500,000 Men, Full Cooperation With Germany's Foes
- John Milton Cooper, Jr., Woodrow Wilson: A Biography (2011) pp. 383–89
- Simon Newton Dexter North; et al. (1918). The American Year Book: A Record of Events and Progress. Thomas Nelson & Sons. pp. 10–11.
- Petkov 1991, p. 44.
- Ambrosius, Lloyd E. "Woodrow Wilson and George W. Bush: Historical Comparisons of Ends and Means in Their Foreign Policies," Diplomatic History, 30 (June 2006), 509–43.
- Arnett, Alex Mathews. Claude Kitchin and the Wilson War Policies. 1937. OCLC 1278853Kitchen was an antiwar Democrat in the House
- Bassett, John Spencer. Our War with Germany: A History (1919) online edition
- Brands, H.W. Theodore Roosevelt (2001) OCLC 50431515, full biography online edition
- Clements, Kendrick A. "Woodrow Wilson and World War I," Presidential Studies Quarterly 34:1 (2004). pp. 62+. online edition
- Clifford, J. Garry. Citizen Soldiers: The Plattsburgh Training Camp Movement, 1913–1920 (1972)
- Cooper, John Milton. The vanity of power: American isolationism and the First World War, 1914-1917 (1969).
- Cooper, John Milton. Woodrow Wilson. A Biography (2009), Major scholarly biography.
- Costrell, Edwin. How Maine viewed the war, 1914–1917, (1940) OCLC 475605726
- Crighton, John C. Missouri and the World War, 1914–1917: a study in public opinion (University of Missouri, 1947) OCLC 831309569
- Coffman, Edward M. The War to End All Wars: The American Military Experience in World War I (1998) ISBN 0-8131-0955-8 OCLC 38842092
- Cummins, Cedric Clisten. Indiana public opinion and the World War, 1914–1917, (1945)
- Davis, Allen F. American Heroine: The Life and Legend of Jane Addams. (Oxford University Press, 1973) ISBN 0-19-501694-7 OCLC 714527
- Doenecke, Justus D. Nothing Less Than War: A New History of America's Entry into World War I (2011) 433 pages; comprehensive history online ISBN 978-0-8131-3002-6 OCLC 682895305
- Doenecke, Justus D. "Neutrality Policy and the Decision for War." in Ross Kennedy ed., A Companion to Woodrow Wilson (2013) pp. 243–69 Online; covers the historiography
- Early, Frances H. A World without War: How U.S. Feminists and Pacifists Resisted World War I. (Syracuse University Press, 1997) ISBN 0-8156-2764-5 OCLC 36800616
- Esposito, David M. The Legacy of Woodrow Wilson: American War Aims in World War I. (Praeger, 1996) 159pp online edition ISBN 0-275-95493-5 OCLC 33244422
- Finnegan, John P. Against the Specter of a Dragon: The Campaign for American Military Preparedness, 1914–1917. (1975). ISBN 0-8371-7376-0 OCLC 983933
- Floyd, M. Ryan (2013). Abandoning American Neutrality: Woodrow Wilson and the Beginning of the Great War, August 1914-December 1915. New York: Palgrave Macmillan. ISBN 978-1-137-33411-4 OCLC 836748335
- Fordham, Benjamin O. "Revisionism reconsidered: exports and American intervention in World War I." International Organization 61#2 (2007): 277-310.
- Gibbs, Christopher C. The Great Silent Majority: Missouri's Resistance to World War I. 1988. ISBN 0-8262-0683-2 OCLC 17676727
- Grubbs, Frank L. The Struggle for Labor Loyalty: Gompers, the A. F. of L., and the Pacifists, 1917–1920. 1968. OCLC 640024383
- Hannigan, Robert E. The Great War and American Foreign Policy, 1914-24 (2016) excerpt; online at Questia
- Herman, Sondra. Eleven Against War: Studies in American Internationalist Thought, 1898–1921. 1969. OCLC 23333
- Higham, Robin and Dennis E. Showalter, eds. Researching World War I: A Handbook. 2003. ISBN 0-313-28850-X OCLC 51922814, 475pp; highly detailed historiography, online edition
- Hodgson, Godfrey. Woodrow Wilson's Right Hand: The Life of Colonel Edward M. House. 2006. ISBN 0-300-09269-5 OCLC 61864854 335pp
- Kazal, Russell A. Becoming Old Stock: The Paradox of German-American Identity. 2004. 390, pp. ISBN 0-691-05015-5 OCLC 52509620 German Americans in Philadelphia ponder the war.
- Kazin, Michael. War Against War: The American Fight for Peace, 1914-1918 (2017).
- Keene, Jennifer D. "Remembering the "Forgotten War": American Historiography on World War I." Historian 78#3 (2016): 439–468.
- Keene, Jennifer D. "Americans Respond: Perspectives on the Global War, 1914-1917." Geschichte und Gesellschaft 40.2 (2014): 266-286. online
- Kennedy, David M. Over Here: The First World War and American Society (1982), covers politics & economics & society online edition ISBN 0-19-502729-9 OCLC 6085939
- Kennedy, Ross A. "Preparedness," in Ross A. Kennedy ed., A Companion to Woodrow Wilson 2013. pp. 270–86 ISBN 978-1-4443-3737-2 OCLC 808244737
- Kennedy, Ross A. Woodrow Wilson, World War I, and America’s Strategy for Peace and Security (2009).
- Koistinen, Paul. Mobilizing for Modern War: The Political Economy of American Warfare, 1865–1919 Lawrence: University Press of Kansas, 1997.
- Knock, Thomas J. To End All Wars: Woodrow Wilson and the Quest for a New World Order New York : Oxford University Press, 1992. ISBN 0-19-507501-3 OCLC 25317305
- Lemnitzer, Jan Martin. "Woodrow Wilson’s Neutrality, the Freedom of the Seas, and the Myth of the 'Civil War Precedents'." Diplomacy & Statecraft 27.4 (2016): 615-638.
- Link, Arthur S. Woodrow Wilson and the Progressive Era, 1910–1917. 1972.
- Link, Arthur S. Wilson: The Struggle for Neutrality: 1914–1915 (1960); Wilson: Confusions and Crises: 1915–1916 (1964); Wilson: Campaigns for Progressivism and Peace: 1916–1917 (1965) all 3 volumes are online at ACLS e-books
- Link, Arthur S. Wilson the Diplomatist: A Look at His Major Foreign Policies Baltimore: Johns Hopkins Press, 1957. online edition OCLC 475072
- Link, Arthur S. Woodrow Wilson and a Revolutionary World, 1913–1921. 1982. online edition
- Link, Arthur S. Woodrow Wilson: Revolution, War, and Peace. Arlington Heights, IL: AHM Pub. Corp., 1979. online edition ISBN 0-88295-798-8 OCLC 5244770
- Livermore, Seward W. Politics Is Adjourned: Woodrow Wilson and the War Congress, 1916–1918. 1966.
- Luebke, Frederick C. Bonds of Loyalty: German-Americans and World War I. Dekalb : Northern Illinois University Press, 1974. ISBN 0-87580-045-9 OCLC 865969
- McCallum, Jack. Leonard Wood: Rough Rider, Surgeon, Architect of American Imperialism. New York : New York University Press, 2006. ISBN 978-0-8147-5699-7 OCLC 60402000
- McDonald, Forrest. Insull: The Rise and Fall of a Billionaire Utility Tycoon (2004)
- May, Ernest R. The World War and American Isolation, 1914–1917 (1959) online at ACLS e-books, highly influential study
- Nash, George H. Life of Herbert Hoover: The Humanitarian, 1914–1917 (Life of Herbert Hoover, Vol. 2) (1988)
- O'Toole, Patricia. When Trumpets Call: Theodore Roosevelt after the White House. New York : Simon & Schuster, 2005. ISBN 0-684-86477-0 OCLC 56921011
- Perkins, Bradford. The Great Rapprochement: England and the United States, 1895–1914 1968.
- Peterson, H. C. Propaganda for War: The Campaign Against American Neutrality, 1914–1917. Norman, OK: University of Oklahoma Press, 1968.
- Petkov, Petko M. (1991). The United States and Bulgaria in World War I. Boulder: Eastern European Monographs.
- Rothwell, V. H. British War Aims and Peace Diplomacy, 1914–1918. 1971.
- Safford, Jeffrey J. Wilsonian Maritime Diplomacy, 1913–1921. 1978.
- Smith, Daniel. The Great Departure: The United States and World War I, 1914–1920. 1965.
- Sterba, Christopher M. Good Americans: Italian and Jewish Immigrants during the First World War. 2003. 288 pp. online edition ISBN 0-19-514754-5 OCLC 49576532
- Tuchman, Barbara W. (1985). The Zimmermann Telegram. ISBN 0-345-32425-0.
- Tucker, Robert W. Woodrow Wilson and the Great War: Reconsidering America's Neutrality, 1914–1917. 2007. ISBN 978-0-8139-2629-2
- Unger, Nancy C. Fighting Bob La Follette: The Righteous Reformer Chapel Hill: University of North Carolina Press, 2000. ISBN 0-8078-2545-X OCLC 42861557
- Venzon, Anne Cipriano, ed. The United States in the First World War: An Encyclopedia New York: Garland Pub., 1995. ISBN 0-8240-7055-0 OCLC 32013365
- Ward, Robert D. "The Origin and Activities of the National Security League, 1914–1919." Mississippi Valley Historical Review 47 (1960): 51–65. online at JSTOR
- Witcover, Jules. Sabotage at Black Tom: Imperial Germany's Secret War in America. Chapel Hill, NC: Algonquin Books of Chapel Hill, 1989. ISBN 0-912697-98-9 OCLC 18379558
- Doenecke, Justus D. "Neutrality Policy and the Decision for War." in Ross Kennedy ed., A Companion to Woodrow Wilson (2013) pp. 243–69 Online; covers the historiography
- Keene, Jennifer D. "Remembering the "Forgotten War": American Historiography on World War I." Historian 78#3 (2016): 439–468.
- Committee on Public Information. How the war came to America (1917) online 840pp
- The Papers of Woodrow Wilson edited by Arthur S. Link complete in 69 vol, at major academic libraries. Annotated edition of all of WW's letters, speeches and writings plus many letters written to him
- Wilson, Woodrow. Why We Are at War (1917) six war messages to Congress, Jan- April 1917
- Keene, Jennifer D.: United States of America , in: 1914-1918-online. International Encyclopedia of the First World War.
- Ford, Nancy Gentile: Civilian and Military Power (USA) , in: 1914-1918-online. International Encyclopedia of the First World War.
- Strauss, Lon: Social Conflict and Control, Protest and Repression (USA) , in: 1914-1918-online. International Encyclopedia of the First World War.
- Little, Branden: Making Sense of the War (USA) , in: 1914-1918-online. International Encyclopedia of the First World War.
- Miller, Alisa: Press/Journalism (USA) , in: 1914-1918-online. International Encyclopedia of the First World War.
- Wells, Robert A.: Propaganda at Home (USA) , in: 1914-1918-online. International Encyclopedia of the First World War.
- NY Times main headline, April 2, 1917, President Calls for War Declaration, Stronger Navy, New Army of 500,000 Men, Full Cooperation With Germany's Foes
- President Wilson's War Address
- Map of Europe at the time of the US declaration of war on Germany at omniatlas.com
- World War I: Declarations of War from Around the Globe - How America Entered the Great War
- Today in History: U.S. Enters World War I