The "51st state", in post-1959 American political discourse, is a phrase that refers to areas or locales that are – seriously or facetiously – considered candidates for U.S. statehood, joining the 50 states that presently compose the United States. The phrase has been applied to external territories as well as parts of existing states which would be admitted as separate states in their own right.
The phrase "51st state" sometimes has international political connotations not necessarily having to do with becoming a U.S. state. The phrase "51st state" can be used in a positive sense, meaning that a region or territory is so aligned, supportive, and conducive with the United States, that it is like a U.S. state. It can also be used in a pejorative sense, meaning an area or region is perceived to be under excessive American cultural or military influence or control. In various countries around the world, people who believe their local or national culture has become too Americanized sometimes use the term "51st state" in reference to their own countries. 
Voters in Washington, D.C. and Puerto Rico have both voted for statehood in referendums.   As statehood candidates, their admission to the Union requires congressional approval.  American Samoa, Guam, the Northern Mariana Islands, and the United States Virgin Islands are also U.S. territories and could potentially become U.S. states someday. 
- 1 Legal requirements
- 2 Puerto Rico
- 3 Guam
- 4 Other territories
- 5 District of Columbia
- 6 By status changes of former U.S. territories
- 7 By partition of or secession from current U.S. states
8 Use internationally
- 8.1 North America
- 8.2 Asia
- 8.3 Europe
- 8.4 Oceania
- 9 From terra nullius
- 10 In popular culture
- 11 See also
- 12 Notes
- 13 External links
Article IV, Section 3, Clause 1 of the United States Constitution authorizes Congress to admit new states into the United States (beyond the thirteen already in existence at the time the Constitution went into effect in 1788). Historically, most new states brought into being by Congress have been established from an organized incorporated territory, created and governed by Congress.  In some cases, an entire territory became a state; in others some part of a territory became a state. As defined in a 1953 U.S. Senate Committee on Interior and Insular Affairs, the traditionally accepted requirements for statehood are:
- The inhabitants of the proposed new state are imbued with and are sympathetic toward the principles of democracy as exemplified in the American form of Government.
- A majority of the electorate wish statehood.
- The proposed new state has sufficient population and resources to support state government and…carry its share of the cost of Federal Government. 
In most cases, the organized government of a territory made known the sentiment of its population in favor of statehood, usually by referendum. Congress then directed that government to organize a constitutional convention to write a state constitution. Upon acceptance of that constitution, by the people of the territory and then by Congress, would adopt a joint resolution granting statehood and the President would issue a proclamation announcing that a new state has been added to the Union. While Congress, which has ultimate authority over the admission of new states, has usually followed this procedure, there have been occasions (due to unique case-specific circumstances) where it did not. 
Puerto Rico has been discussed as a potential 51st state of the United States. In a 2012 status referendum a majority of voters, 54%, expressed dissatisfaction with the current political relationship. In a separate question, 61% of voters supported statehood (excluding the 26% of voters who left this question blank). On December 11, 2012, Puerto Rico's legislature resolved to request that the President and the U.S. Congress act on the results, end the current form of territorial status and begin the process of admitting Puerto Rico to the Union as a state.  On January 4, 2017, Puerto Rico's new representative to Congress pushed a bill that would ratify statehood by 2025. 
On June 11, 2017, another non-binding referendum was held where 97.7 percent voted and favored the statehood option. The turnout for this vote was a low 23 percent, but some leaders of the New Progressive Party say this is because of migration of Puerto Ricans to the mainland. This referendum was boycotted by the other two parties of opposition.
On June 27, 2018, the H.R. 6246 Act was introduced on the U.S. House with the purpose of responding to, and complying with, the democratic will of the United States citizens residing in Puerto Rico as expressed in the plebiscites held on November 6, 2012, and June 11, 2017, by setting forth the terms for the admission of the territory of Puerto Rico as a State of the Union.  The admission act has 37 original cosponsors between Republicans and Democrats in the U.S. House of Representatives. 
Since 1898, Puerto Rico has had limited representation in the United States Congress in the form of a Resident Commissioner, a nonvoting delegate. The 110th Congress returned the Commissioner's power to vote in the Committee of the Whole, but not on matters where the vote would represent a decisive participation.  Puerto Rico has elections on the United States presidential primary or caucus of the Democratic Party and the Republican Party to select delegates to the respective parties' national conventions although presidential electors are not granted on the Electoral College. As American citizens, Puerto Ricans can vote in U.S. presidential elections, provided they reside in one of the 50 states or the District of Columbia and not in Puerto Rico itself.
Residents of Puerto Rico pay U.S. federal taxes: import and export taxes, federal commodity taxes, social security taxes, thereby contributing to the American Government. Most Puerto Rico residents do not pay federal income tax but do pay federal payroll taxes ( Social Security and Medicare). However, federal employees, those who do business with the federal government, Puerto Rico–based corporations that intend to send funds to the U.S. and others do pay federal income taxes. Puerto Ricans may enlist in the U.S. military. Puerto Ricans have participated in all American wars since 1898; 52 Puerto Ricans had been killed in the Iraq War and War in Afghanistan by November 2012. 
Puerto Rico has been under U.S. sovereignty for over a century after it was ceded to the U.S. by Spain following the end of the Spanish–American War, and Puerto Ricans have been U.S. citizens since 1917. The island's ultimate status has not been determined as of 2012 [update], and its residents do not have voting representation in their federal government. Puerto Rico has limited representation in the U.S. Congress in the form of a Resident Commissioner, a delegate with limited no voting rights.  Like the states, Puerto Rico has self-rule, a republican form of government organized pursuant to a constitution adopted by its people, and a bill of rights.
This constitution was created when the U.S. Congress directed local government to organize a constitutional convention to write the Puerto Rico Constitution in 1951. The acceptance of that constitution by Puerto Rico's electorate, the U.S. Congress, and the U.S. president occurred in 1952. In addition, the rights, privileges and immunities attendant to United States citizens are "respected in Puerto Rico to the same extent as though Puerto Rico were a State of the Union" through the express extension of the Privileges and Immunities Clause of the U.S. Constitution by the U.S. Congress in 1948. 
Puerto Rico is designated in its constitution as the "Commonwealth of Puerto Rico".  The Constitution of Puerto Rico, which became effective in 1952, adopted the name of Estado Libre Asociado (literally translated as "Free Associated State"), officially translated into English as Commonwealth, for its body politic.   The island is under the jurisdiction of the Territorial Clause of the U.S. Constitution, which has led to doubts about the finality of the Commonwealth status for Puerto Rico. In addition, all people born in Puerto Rico become citizens of the U.S. at birth (under provisions of the Jones–Shafroth Act in 1917), but citizens residing in Puerto Rico cannot vote for the President of the United States nor for full members of either house of Congress. Statehood would grant island residents full voting rights at the federal level. The Puerto Rico Democracy Act (H.R. 2499) was approved on April 29, 2010, by the United States House of Representatives (223–169),  but was not approved by the Senate before the end of the 111th Congress. It would have provided for a federally sanctioned self-determination process for the people of Puerto Rico. This act would provide for referendums to be held in Puerto Rico to determine the island's ultimate political status. It had also been introduced in 2007. 
|Puerto Rican status referendum, 2012|
|Date||November 6, 2012|
simple majority for the first question|
first-past-the-post for the second question
|Should Puerto Rico continue its current territorial status?|
|Which non-territorial option do you prefer?|
In November 2012, a referendum resulted in 54 percent of respondents voting to reject the current status under the territorial clause of the U.S. Constitution,  while a second question resulted in 61 percent of voters identifying statehood as the preferred alternative to the current territorial status.  The 2012 referendum was by far the most successful referendum for statehood advocates and support for statehood has risen in each successive popular referendum.   However, more than one in four voters abstained from answering the question on the preferred alternative status. Statehood opponents have argued that the statehood option garnered only 45 percent of the votes if abstentions are included.  If abstentions are considered, the result of the referendum is much closer to 44 percent for statehood, a number that falls under the 50 percent majority mark. 
The Washington Post, The New York Times and the Boston Herald have published opinion pieces expressing support for the statehood of Puerto Rico.    On November 8, 2012, Washington, D.C. newspaper The Hill published an article saying that Congress will likely ignore the results of the referendum due to the circumstances behind the votes.  U.S. Congressman Luis Gutiérrez and U.S. Congresswoman Nydia Velázquez, both of Puerto Rican ancestry, agreed with The Hill's statements.  Shortly after the results were published, Puerto Rico-born U.S. Congressman José Enrique Serrano commented "I was particularly impressed with the outcome of the 'status' referendum in Puerto Rico. A majority of those voting signaled the desire to change the current territorial status. In a second question an even larger majority asked to become a state. This is an earthquake in Puerto Rican politics. It will demand the attention of Congress, and a definitive answer to the Puerto Rican request for change. This is a history-making moment where voters asked to move forward." 
Several days after the referendum, the Resident Commissioner Pedro Pierluisi, Governor Luis Fortuño, and Governor-elect Alejandro García Padilla wrote separate letters to the President of the United States, Barack Obama, addressing the results of the voting. Pierluisi urged Obama to begin legislation in favor of the statehood of Puerto Rico, in light of its win in the referendum.  Fortuño urged him to move the process forward.  García Padilla asked him to reject the results because of their ambiguity.  The White House stance related to the November 2012 plebiscite was that the results were clear, the people of Puerto Rico want the issue of status resolved, and a majority chose statehood in the second question. Former White House director of Hispanic media stated, "Now it is time for Congress to act and the administration will work with them on that effort, so that the people of Puerto Rico can determine their own future." 
On May 15, 2013, Resident Commissioner Pierluisi introduced H.R. 2000 to Congress to "set forth the process for Puerto Rico to be admitted as a state of the Union", asking for Congress to vote on ratifying Puerto Rico as the 51st state.  On February 12, 2014, Senator Martin Heinrich introduced a bill in the U.S. Senate. The bill would require a binding referendum to be held in Puerto Rico asking whether the territory wants to be admitted as a state. In the event of a yes vote, the president would be asked to submit legislation to Congress to admit Puerto Rico as a state. 
On January 15, 2014, the United States House of Representatives approved $2.5 million in funding to hold a referendum. This referendum can be held at any time as there is no deadline by which the funds have to be used.  The United States Senate then passed the bill which was signed into law on January 17, 2014, by Barack Obama, then President of the United States. 
|Puerto Rican status referendum, 2017|
|Date||June 11, 2017|
The previous plebiscites provided voters with three options: statehood, free association, and independence. The Puerto Rican status referendum of 2017 originally offered only two options: Statehood and Independence/Free Association, however a "current territorial status" was added before the referendum took place. The referendum was held on June 11, 2017, with an overwhelming majority of voters supporting statehood at 97.16%, however with a voter turnout of 22.99%, a historical low. If the majority voted for Independence/Free Association, a second vote would have been held to determine the preference: full independence as a nation or associated free state status with independence but with a "free and voluntary political association" between Puerto Rico and the United States. The specifics of the association agreement  would be detailed in the Compact of Free Association that would be negotiated between the U.S. and Puerto Rico. That document might cover topics such as the role of the U.S. military in Puerto Rico, the use of the U.S. currency, free trade between the two entities, and whether Puerto Ricans would be U.S. citizens. 
Governor Ricardo Rosselló is strongly in favor of statehood to help develop the economy and help to "solve our 500-year-old colonial dilemma ... Colonialism is not an option .... It's a civil rights issue ... 3.5 million citizens seeking an absolute democracy," he told the news media.  Benefits of statehood include an additional $10 billion per year in federal funds, the right to vote in presidential elections, higher Social Security and Medicare benefits, and a right for its government agencies and municipalities to file for bankruptcy. The latter is currently prohibited. 
At approximately the same time as the referendum, Puerto Rico's legislators are also expected to vote on a bill that would allow the Governor to draft a state constitution and hold elections to choose senators and representatives to the United States Congress. Regardless of the outcome of the referendum or the bill on drafting a constitution, action by Congress would be necessary to implement changes to the status of Puerto Rico under the Territorial Clause of the United States Constitution. 
If the majority of Puerto Ricans were to choose the Free Association option – and only 33% voted for it in 2012 – and if it were granted by the U.S. Congress, Puerto Rico would become a Free Associated State, a virtually independent nation. It would have a political and economical treaty of association with the U.S. that would stipulate all delegated agreements. This could give Puerto Rico a similar status to Micronesia, the Marshall Islands, and Palau, countries which currently have a Compact of Free Association with the United States.
Those Free Associated States use the American dollar, receive some financial support and the promise of military defense if they refuse military access to any other country. Their citizens are allowed to work in the U.S. and serve in its military. 
On June 11, 500,000 Puerto Ricans voted for statehood, 7,600 voted for independence, and 6,700 voted for status quo. 
On June 27, 2018, Jenniffer González-Colón, Puerto Rico's non-voting member of Congress, introduced the Puerto Rico Admission Act of 2018 (HR 6246) to Congress to admit Puerto Rico as a US state. The legislation would create a taskforce to repeal or amend any existing laws that have unequal application between Puerto Rico and the several States to phase in equality for Puerto Rico. Under this legislation (if passed), Puerto Rico would become incorporated (from its current unincorporated status) while equality with US States is phased in and Puerto Rico would fully become a US State by January 2021.  The bill introduced into the House has bipartisan support with 37 cosponsors, including 22 Republicans and 15 Democrats.  Jenniffer Gonzalez-Colon is the Resident Commissioner of Puerto Rico. The Resident Commissioner is elected by the people of Puerto Rico to serve in the US House of Representatives but does not have full voting power, due to its unequal status as a US territory.  The legislation cites the two referenda Puerto Rico voted on in favor of Statehood to call on Congress to admit Puerto Rico as a State as an expression of the will of the people in the territory.
Guam (formally the Territory of Guam) is an unincorporated and organized territory of the United States. Located in the western Pacific Ocean, Guam is one of five American territories with an established civilian government.  
In the 1980s and early 1990s, there was a significant movement in favor of this U.S. territory becoming a commonwealth, which would give it a level of self-government similar to Puerto Rico and the Northern Mariana Islands. However, the federal government rejected the version of a commonwealth that the government of Guam proposed, because its clauses were incompatible with the Territorial Clause (Art. IV, Sec. 3, cl. 2) of the U.S. Constitution. Other movements advocate U.S. statehood for Guam, union with the state of Hawaii, or union with the Northern Mariana Islands as a single territory, or independence. 
In a 1982 plebiscite, voters indicated interest in seeking commonwealth status but seemed not to understand the ramifications of such a change. The island has been considering another non-binding plebiscite on decolonization since 1998. Governor Eddie Baza Calvo intended to include one during the island's November 2016 elections but it was delayed again. 
A Commission on Decolonization was established in 1997 to educate the people of Guam about the various political status options in its relationship with the U.S.: statehood, free association and independence. The group was dormant for some years. In 2013, the Commission began seeking funding to start a public education campaign. There were few subsequent developments until late 2016. In early December 2016, the Commission scheduled a series of education sessions in various villages about the current status of Guam's relationship with the U.S. and the self-determination options that might be considered.  The Commission's current Executive Director is Edward Alvarez and there are ten members. The group is also expected to release position papers on independence and statehood but the contents have not yet been completed. 
Guam has been occupied for over 450 years by the Spanish, the Japanese, and the United States. In 2016, Governor Eddie Calvo planned a decolonization referendum that the indigenous Chamorro people of Guam would solely participate in, in which the three options would be given, including statehood, independence, and free association. However, this referendum for the Chamorro people was struck down by a federal judge on the grounds of racial discrimination. In the wake of this ruling, Governor Calvo has suggested that two ballots be held: one for the Chamorro People and one for eligible U.S. citizens who are non-indigenous residents of Guam. The Governor hopes for a decolonization plebiscite to occur in 2018.    It is also possible that in 2018, Guam and its neighbor, the Northern Mariana Islands (a U.S. Commonwealth) may vote on a reunification referendum.  
The United Nations is in favor of greater self-determination for Guam and other such territories. The UN's Special Committee on Decolonization has agreed to endorse the Governor's education plan. The commission's May 2016 report states: "With academics from the University of Guam, [the Commission] was working to create and approve educational materials. The Office of the Governor was collaborating closely with the Commission" in developing educational materials for the public. 
The United States Department of the Interior had approved a $300,000 grant for decolonization education, Edward Alvarez told the United Nations Pacific Regional Seminar in May 2016. "We are hopeful that this might indicate a shift in [United States] policy to its Non-Self-Governing Territories such as Guam, where they will be more willing to engage in discussions about our future and offer true support to help push us towards true self-governances and self-determination." 
Washington, D.C. is often mentioned as a candidate for statehood. In Federalist No. 43 of The Federalist Papers, James Madison considered the implications of the definition of the "seat of government" found in the United States Constitution. Although he noted potential conflicts of interest, and the need for a "municipal legislature for local purposes",  Madison did not address the district's role in national voting. Legal scholars disagree on whether a simple act of Congress can admit the District as a state, due to its status as the seat of government of the United States, which Article I, Section 8 of the Constitution requires to be under the exclusive jurisdiction of Congress; depending on the interpretation of this text, admission of the full District as a state may require a Constitutional amendment, which is much more difficult to enact.  However, the Constitution does not set a minimum size for the District. Its size has already changed once before, when Virginia reclaimed the portion of the District south of the Potomac. So the constitutional requirement for a federal district can be satisfied by reducing its size to the small central core of government buildings and monuments.[ citation needed]
Washington, D.C. residents who support the statehood movement sometimes use a shortened version of the Revolutionary War protest motto " No taxation without representation", omitting the initial "No", denoting their lack of Congressional representation; the phrase is now printed on newly issued Washington, D.C. license plates (although a driver may choose to have the District of Columbia website address instead). President Bill Clinton's presidential limousine had the "Taxation without representation" license plate late in his term, while President George W. Bush had the vehicle's plates changed shortly after beginning his term in office.  President Barack Obama had the license plates changed back to the protest style shortly before his second-term inauguration.  President Donald Trump continued to use the plates as of his inauguration, though he stated he had "no position" regarding statehood or representation for the District. 
This position was carried by the D.C. Statehood Party, a political party; it has since merged with the local Green Party affiliate to form the D.C. Statehood Green Party. The nearest this movement ever came to success was in 1978, when Congress passed the District of Columbia Voting Rights Amendment. Two years later in 1980, local citizens passed an initiative calling for a constitutional convention for a new state. In 1982, voters ratified the constitution of the state, which was to be called New Columbia. The drive for statehood stalled in 1985, however, when the District of Columbia Voting Rights Amendment failed because not enough states ratified the amendment within the seven-year span specified.
Another proposed option would be to have Maryland, from which the current land was ceded, retake the District of Columbia, as Virginia has already done for its part, while leaving the National Mall, the United States Capitol, and the White House in a truncated District of Columbia.  This would give residents of the District of Columbia the benefit of statehood while precluding the creation of a 51st state. The requirement that Maryland consent to a change in its borders makes this unlikely[ citation needed].
|District of Columbia statehood referendum, 2016|
|Location||District of Columbia|
|Date||November 8, 2016|
|Voting system||simple majority|
|Shall the voters of the District of Columbia advise the Council to approve or reject this proposal?|
On April 15, 2016, District Mayor Muriel Bowser called for a citywide vote on whether the nation's capital should become the 51st state.  This was followed by the release of a proposed State Constitution.  This Constitution would make the Mayor of the District of Columbia the Governor of the proposed state, while the members of the City Council would make up the proposed House of Delegates. While the name "New Columbia" has long been associated with the movement, community members thought other names, such as Potomac or Douglass, were more appropriate for the area. 
On November 8, 2016, the voters of the District of Columbia voted overwhelmingly in favor of statehood, with 86% of voters voting to advise approving the proposal. 
The Philippines has had small grassroots movements for U.S. statehood.  Originally part of the platform of the Progressive Party, then known as the Federalista Party, the party dropped it in 1907, which coincided with the name change.   In 1981, the presidential candidate for the Federal Party ran on a platform of Philippine Statehood.  As recently as 2004, the concept of the Philippines becoming a U.S. state has been part of a political platform in the Philippines.  Supporters of this movement include Filipinos who believe that the quality of life in the Philippines would be higher and that there would be less poverty there if the Philippines were an American state or territory. Supporters also include Filipinos that had fought as members of the United States Armed Forces in various wars during the Commonwealth period.  
The Philippine statehood movement had a significant impact during the early American colonial period.  It is no longer a mainstream movement,  but is a small social movement that gains interest and talk in that nation. 
There exist several proposals to divide states with regions that are politically or culturally divergent into smaller, more homogeneous, administratively efficient entities.  Splitting a state requires the approval of both its legislature and the U.S. Congress. 
Proposals of new states by partition include:
- Arizona: The secession of Pima County in Arizona, with the hopes of neighboring counties Cochise, Yuma, and Santa Cruz joining to form a state. 
- California and Oregon:
- The secession of Northern California and Southern Oregon to form a state named Jefferson.
- Various proposals of partition and secession in California, usually splitting the south half from the north or the urban coastline from the rest of the state.  In 2014, businessperson Tim Draper collected signatures for a petition to split California into six different states,  but not enough to qualify for the ballot.  Tim Draper attempted a follow-up petition to split California into three states in 2018.   However, the initiative to divide California into three states was ordered removed from the 2018 ballot by the California Supreme Court, as the California constitution does not allow this type of action to be undertaken as a ballot initiative.   
- Colorado: In 2013, commissioners in Weld County, Colorado announced a proposal to leave Colorado along with neighboring counties, and form the state of North Colorado.  The counties in contention voted to begin plans for secession that November, with mixed results. 
- Delaware, Maryland and Virginia: The secession of several counties from the eastern shores of Maryland and Virginia, combining with some or all of the state of Delaware, forming a state named Delmarva. 
- Florida: The secession of South Florida and the Greater Miami area to form a state named South Florida. The region has a population of over 7 million, comprising 41% of Florida's population. 
- The secession of Cook County, which contains Chicago, from Illinois to form a separate state, proposed by residents of the more Republican Downstate Illinois to free it from the political influence of the heavily Democratic Chicago area. 
- The secession of Southern Illinois from the rest of the state, south of Springfield, with the capital in Mt. Vernon.
- Maryland: The secession of five counties on the western side of the state due to political differences with the more liberal central part of the state. 
- Michigan: The secession of the geographically separate and culturally distinct Upper Peninsula of Michigan from the Lower Peninsula, as a state called Superior.
- New York: Various proposals partitioning New York into separate states, all of which involve to some degree the separation of New York City from the rest of the state. 
- Texas: Under the resolution by which the Republic of Texas was admitted to the Union and the state constitution, it has the right to divide itself into up to five states. There were a significant number of Texans who supported dividing the state in its early decades, called divisionists.    Current Texas politics and self-image make any tampering with Texas' status as the largest state by land area in the contiguous United States unlikely.   
- Washington: Dividing the state into Western Washington and Eastern Washington via the Cascade Mountains. Suggested names include East Washington, Lincoln, and Cascadia.
- The National Movement for the Establishment of a 49th State, founded by Oscar Brown, Sr. and Bradley Cyrus, and active in Chicago between 1934 and 1937, had the aim of forming an African-American state in the South.  
Some countries, because of their cultural similarities and close alliances with the United States, are often described as a 51st state. In other countries around the world, movements with various degrees of support and seriousness have proposed U.S. statehood.
In Canada, "the 51st state" is a phrase generally used in such a way as to imply that if a certain political course is taken, Canada's destiny will be as little more than a part of the United States. Examples include the Canada–United States Free Trade Agreement in 1988, the debate over the creation of a common defense perimeter, and as a potential consequence of not adopting proposals intended to resolve the issue of Quebec sovereignty, the Charlottetown Accord in 1992 and the Clarity Act in 1999.
The phrase is usually used in local political debates, in polemic writing or in private conversations. It is rarely used by politicians themselves in a public context, although at certain times in Canadian history political parties have used other similarly loaded imagery. In the 1988 federal election, the Liberals asserted that the proposed Free Trade Agreement amounted to an American takeover of Canada —notably, the party ran an ad in which Progressive Conservative (PC) strategists, upon the adoption of the agreement, slowly erased the Canada-U.S. border from a desktop map of North America.  Within days, however, the PCs responded with an ad which featured the border being drawn back on with a permanent marker, as an announcer intoned "Here's where we draw the line." 
The implication has historical basis and dates to the breakup of British America during the American Revolution. The colonies that had confederated to form the United States invaded Canada (at the time a term referring specifically to the modern-day provinces of Quebec and Ontario, which had only been in British hands since 1763) at least twice, neither time succeeding in taking control of the territory. The first invasion was during the Revolution, under the assumption that French-speaking Canadians' presumed hostility towards British colonial rule combined with the Franco-American alliance would make them natural allies to the American cause; the Continental Army successfully recruited two Canadian regiments for the invasion. That invasion's failure forced the members of those regiments into exile, and they settled mostly in upstate New York. The Articles of Confederation, written during the Revolution, included a provision for Canada to join the United States, should they ever decide to do so, without needing to seek U.S. permission as other states would.  The United States again invaded Canada during the War of 1812, but this effort was made more difficult due to the large number of Loyalist Americans that had fled to what is now Ontario and still resisted joining the republic. The Hunter Patriots in the 1830s and the Fenian raids after the American Civil War were private attacks on Canada from the U.S.  Several U.S. politicians in the 19th century also spoke in favour of annexing Canada. 
In the late 1940s, during the last days of the Dominion of Newfoundland (at the time a dominion-dependency in the Commonwealth and independent of Canada), there was mainstream support, although not majority, for Newfoundland to form an economic union with the United States, thanks to the efforts of the Economic Union Party and significant U.S. investment in Newfoundland stemming from the U.S.-British alliance in World War II. The movement ultimately failed when, in a 1948 referendum, voters narrowly chose to confederate with Canada (the Economic Union Party supported an independent "responsible government" that they would then push toward their goals).
A few groups in Canada have actively campaigned in favor of joining the United States. These annexationist movements have not attracted large mainstream attention, although surveys have found that a small minority of Canadians expressed support for the concept in surveys done by Léger Marketing in 2001  and in 2004. 
In the United States, the term "the 51st state" when applied to Canada can serve to highlight the similarities and close relationship between the United States and Canada. Sometimes the term is used disparagingly, intended to deride Canada as an unimportant neighbor. In the Quebec general election, 1989, the political party Parti 51 ran 11 candidates on a platform of Quebec seceding from Canada to join the United States (with its leader, André Perron, claiming Quebec could not survive as an independent nation).  The party attracted just 3,846 votes across the province, 0.11% of the total votes cast.  In comparison, the other parties in favour of sovereignty of Quebec in that election got 40.16% (PQ) and 1.22% (NPDQ).
In 1847–48, with the United States occupying Mexico at the conclusion of the Mexican–American War, there was talk in Congress of annexing the entirety of Mexico. The result was the Mexican Cession, also called the Treaty of Guadalupe Hidalgo for the town in which the treaty was signed, in which the U.S. annexed over 40% of Mexico. Talk of annexing all of Mexico disappeared after this time. In 1848 a bill was debated in congress that would have annexed the Republic of Yucatán, but a vote failed to take place. 
Due to geographical proximity of the Central American countries to the U.S. which has powerful military, economic, and political influences, there were several movements and proposals by the United States during the 19th and 20th centuries to annex some or all of the Central American republics ( Costa Rica, El Salvador, Guatemala, Honduras with the formerly British-ruled Bay Islands, Nicaragua, Panama which had the U.S.-ruled Canal Zone territory from 1903 to 1979, and Belize, which is a constitutional monarchy and was known as British Honduras until 1981). However, the U.S. never acted on these proposals from some U.S. politicians; some of which were never delivered or considered seriously. In 2001, El Salvador adopted the U.S. dollar as its currency, while Panama has used it for decades due to its ties to the Canal Zone.
In 1854 the Ostend Manifesto was written, outlining the rationale for the U.S. to purchase Cuba from Spain, implying taking the island by force if Spain refused. Once the document became published many northern states denounced the document.
Cuba, like many Spanish territories, wanted to break free from Spain. A pro-independence movement in Cuba was supported by the U.S., and Cuban guerrilla leaders wanted annexation to the United States, but Cuban revolutionary leader José Martí called for Cuban nationhood. When the U.S. battleship Maine sank in Havana Harbor, the U.S. blamed Spain and the Spanish–American War broke out in 1898. After the U.S. won, Spain relinquished claim of sovereignty over territories, including Cuba. The U.S. administered Cuba as a protectorate until 1902. Several decades later in 1959, the Cuban government of U.S.-backed Fulgencio Batista was overthrown by Fidel Castro who subsequently installed a Marxist–Leninist government. When the U.S. refused to trade with Cuba, Cuba allied with the Soviet Union who imported Cuban sugar, Cuba's main export. The government installed by Fidel Castro has been in power ever since. In 2016, the U.S. eased trade and travel restrictions against Cuba.  United Airlines submitted a formal application to the U.S. Department of Transportation (DOT) for authority to provide service from four of its largest U.S. gateway cities – Newark/New York, Houston, Washington, D.C. and Chicago – to Havana's José Martí International Airport. 
In 1898, one or more news outlets in the Caribbean noted growing sentiments of resentment of British rule in Dominica, including the system of administration over the country. These publications attempted to gauge sentiments of annexation to the United States as a way to change this system of administration. 
During World War II, when Denmark was occupied by Nazi Germany, the United States briefly controlled Greenland for battlefields and protection. In 1946, the United States offered to buy Greenland from Denmark for $100 million ($1.2 billion today) but Denmark refused to sell it.   Several politicians and others have in recent years argued that Greenland could hypothetically be in a better financial situation as a part of the United States; for instance mentioned by professor Gudmundur Alfredsson at University of Akureyri in 2014.   One of the actual reasons behind U.S. interest in Greenland could be the vast natural resources of the island.  According to WikiLeaks, the U.S. appears to be highly interested in investing in the resource base of the island and in tapping the vast expected hydrocarbons off the Greenlandic coast. 
Time columnist Mark Thompson suggested that Haiti had effectively become the 51st state after the 2010 Haiti earthquake, with the widespread destruction prompting a quick and extensive response from the United States, even so far as the stationing of the U.S. military in Haitian air and sea ports to facilitate foreign aid. 
The idea of admission to the United States was discussed among some netizens      alongside proposals of becoming independent (within or outside the Commonwealth, as a republic or a Commonwealth realm),  rejoining the Commonwealth,  confederation with Canada as the eleventh province or the fourth territory (with reference to Ken McGoogan's proposal regarding Scotland),  returning to British rule as a dependent territory,  joining the Republic of China,  or acceding to other federations as a or a number of city-states. However, discussions as such have never entered the mainstream.
Several publications suggested that the Iraq War was a neocolonialist war to make the Republic of Iraq into the 51st U.S. state, though such statements are usually made in a facetious manner, as a tongue-in-cheek statement.     
Several websites assert that Israel is the 51st state due to the annual funding and defense support it receives from the United States. An example of this concept can be found in 2003 when Martine Rothblatt published a book called Two Stars for Peace that argued for the addition of Israel and the Palestinian territories as the 51st and 52nd states in the Union. The American State of Canaan, is a book published by Prof. Alfred de Grazia, political science and sociologist, in March 2009, proposing the creation of the 51st and 52nd states from Israel and the Palestinian territories.
In Article 3 of the Treaty of San Francisco between the Allied Powers and Japan, which came into force in April 1952, the U.S. put the outlying islands of the Ryukyus, including the island of Okinawa—home to over 1 million Okinawans related to the Japanese—and the Bonin Islands, the Volcano Islands, and Iwo Jima into U.S. trusteeship.  All these trusteeships were slowly returned to Japanese rule. Okinawa was returned on May 15, 1972, but the U.S. stations troops in the island's bases as a defense for Japan.
A poll in 2003 among Taiwanese residents aged between 13 and 22 found that, when given the options of either becoming a province of the People's Republic of China or a state within the U.S., 55% of the respondents preferred statehood while only 36% chose joining China.  A group called Taiwan Civil Government, established in Taipei in 2008, claims that the island of Taiwan and other minor islands are the territory of the United States. 
Albania has often been called the 51st state for its perceived strongly pro-American positions, mainly because of the United States' policies towards it.  In reference to President George W. Bush's 2007 European tour, Edi Rama, Tirana's mayor and leader of the opposition Socialists, said: "Albania is for sure the most pro-American country in Europe, maybe even in the world ... Nowhere else can you find such respect and hospitality for the President of the United States. Even in Michigan, he wouldn't be as welcome." At the time of ex-Secretary of State James Baker's visit in 1992, there was even a move to hold a referendum declaring the country as the 51st American state.   In addition to Albania, Kosovo (which is predominately Albanian) is seen as a 51st state due to the heavily presence and influence of the United States. The U.S. has had troops and the largest base outside U.S. territory, Camp Bondsteel, in the territory since 1999.
There was a movement among the Azores archipelago to break away from Portugal and join the United States in the late 19th century through the early 20th century. Feeling that they were being unfairly exploited by the authorities on the mainland, this movement believed the best solution was to have the United States govern them. This movement was fueled by a large number of immigrants to the United States, particularly to the New England states, for labor and educational reasons. Also establishing a close social connection between the Azores and the United States were American whaling companies. New England and New York-based whaling ships frequently used the Azores as an overseas base of operations and employed large number of the local population to man the ships. The movement to have the United States annex the Azores reached its climax during World War I when the United States Navy established a base of operations in the Azores. Sensing that the Americans were doing more to defend the Azores from the Germans than the Portuguese Government was, particularly during the raid of SM U-155 on the Azores in 1917, many local politicians openly demanded a change. American Naval officers and politicians, notably Assistant Secretary of the Navy Franklin Roosevelt, however, dismissed any idea of the United States taking control.
Poland has historically been staunchly pro-American, dating back to General Tadeusz Kościuszko and Casimir Pulaski's involvement in the American Revolution. This pro-American stance was reinforced following favorable American intervention in World War I (leading to the creation of an independent Poland) and the Cold War (culminating in a Polish state independent of Soviet influence). Poland contributed a large force to the "Coalition of the Willing" in Iraq. A quote referring to Poland as "the 51st state" has been attributed to James Pavitt, then Central Intelligence Agency Deputy Director for Operations, especially in connection to extraordinary rendition. 
The Party of Reconstruction in Sicily, which claimed 40,000 members in 1944, campaigned for Sicily to be admitted as a U.S. state.  This party was one of several Sicilian separatist movements active after the downfall of Italian Fascism. Sicilians felt neglected or underrepresented by the Italian government after the annexation of 1861 that ended the rule of the Kingdom of the Two Sicilies based in Naples. The large population of Sicilians in America and the American-led Allied invasion of Sicily in July–August 1943 may have contributed to the sentiment.
In Australia, the term '51st state' is used as a disparagement of a perceived invasion of American cultural or political influence. 
In 2010 there was an attempt to register a 51st State Party with the New Zealand Electoral Commission. The party advocates New Zealand becoming the 51st state of the United States of America. The party's secretary is Paulus Telfer, a former Christchurch mayoral candidate.   On February 5, 2010, the party applied to register a logo with the Electoral Commission.  The logo – a U.S. flag with 51 stars – was rejected by the Electoral Commission on the grounds that it was likely to cause confusion or mislead electors.  As of 2014 [update], the party remains unregistered and cannot appear on a ballot.
There are four categories of terra nullius, land that is unclaimed by any state: the small unclaimed territory of Bir Tawil between Egypt and Sudan, Marie Byrd Land and other small pockets of Antarctica, the high seas, and celestial bodies such as the Moon or Mars. In the last three of these, international treaties (the Antarctic Treaty, the United Nations Convention on the Law of the Sea, and the Outer Space Treaty respectively) prevent colonization and potential statehood of any of these uninhabited (and, given current technology, not permanently inhabitable) territories.
The L5 Society was founded in 1975 with the intention of constructing a space habitat at one of the Lagrangian points of Earth's orbit. Its members successfully lobbied the United States Senate to defeat the Moon Treaty, a treaty that would have transferred sovereignty of all outer space to an international organization, in 1980.  The high price such a project would cost compared to previous Earth-based colonies eventually led to the group's demise in the 1980s.
Related terms have been used in books and film usually used in a negative sense:
- In the alternative universe of Alan Moore's graphic novel Watchmen, the Vietnam War ends with the conquest of the North and annexation of a united Vietnam as the 51st state.
- The British film The 51st State (released in the United States and Canada as Formula 51), makes fun of Anglo-American relations.
The term has also been used in music.
- The 1986 album The Ghost of Cain by the English rock band New Model Army features a track called " 51st State", which refers to Britain under Margaret Thatcher for her perceived pro-Americanism. 
- The 1986 track "Heartland" by English band The The describes an increasingly economically divided Britain as the 51st state of the U.S. 
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With my vote, I make the initial request to the Federal Government to begin the process of the decolonization through: (1) Free Association: Puerto Rico should adopt a status outside of the Territory Clause of the Constitution of the United States that recognizes the sovereignty of the People of Puerto Rico. The Free Association would be based on a free and voluntary political association, the specific terms of which shall be agreed upon between the United States and Puerto Rico as sovereign nations. Such agreement would provide the scope of the jurisdictional powers that the People of Puerto Rico agree to confer to the United States and retain all other jurisdictional powers and authorities. Under this option the American citizenship would be subject to negotiation with the United States Government; (2) Proclamation of Independence, I demand that the United States Government, in the exercise of its power to dispose of territory, recognize the national sovereignty of Puerto Rico as a completely independent nation and that the United States Congress enact the necessary legislation to initiate the negotiation and transition to the independent nation of Puerto Rico. My vote for Independence also represents my claim to the rights, duties, powers, and prerogatives of independent and democratic republics, my support of Puerto Rican citizenship, and a "Treaty of Friendship and Cooperation" between Puerto Rico and the United States after the transition process
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