The Jones–Shafroth Act ( Pub.L. 64–368, 39 Stat. 951, enacted March 2, 1917) —also known as the Jones Act of Puerto Rico, Jones Law of Puerto Rico, or as the Puerto Rican Federal Relations Act of 1917— was an Act of the United States Congress, signed by President Woodrow Wilson on March 2, 1917. [a] The act superseded the Foraker Act and granted U.S. citizenship to anyone born in Puerto Rico on or after April 25, 1898. It also created the Senate of Puerto Rico, established a bill of rights, and authorized the election of a Resident Commissioner (previously appointed by the President) to a four-year term. The act also exempted Puerto Rican bonds from federal, state, and local taxes regardless of where the bond holder resides. [b]
The impetus for this legislation came from a complex of local and mainland interests. Puerto Ricans lacked internationally recognized citizenship; but the local council was wary of "imposing citizenship." Luis Muñoz Rivera,  the Resident Commissioner in Washington, argued against US citizenship, giving several speeches in the House of Representatives.  On 5 May 1916 he demanded:
Give us now the field of experiment which we ask of you… It is easy for us to set up a stable republican government with all possible guarantees for all possible interests. And afterwards, when you… give us our independence… you will stand before humanity as a great creator of new nationalities and a great liberator of oppressed people.
... as you know, the final aspiration of my party is nationalism with or without American protectorate, and as the Puerto Rican people understand it, the granting of (US) citizenship will interfere with their aspirations for independence.
Rep. William Atkinson Jones, (D-Virginia), chairman of the House Committee on Insular Affairs, and Sen. John Shafroth, (D-Colorado), chairman of the Committee on Pacific Islands and Puerto Rico, sponsored the legislation which bears their names.  
This Act made all [Puerto Rican citizenship|citizens of Puerto Rico] U.S. citizens  and reformed the system of [government of Puerto Rico|government in Puerto Rico]. In some respects, the governmental structure paralleled that of a state of the United States. Powers were separated among [Executive branch|executive] , [Judicial branch|judicial], and [legislative branch]es. The law also recognized certain [civil rights] through a [bill of rights] to be observed by the government of Puerto Rico (although [trial by July] was not among them).
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Residents of the island were granted citizenship and allowed to reject it voluntarily within six months of the act being established. Of the almost 1.2 million residents on the island only 288 rejected it. 
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The Act created a legislative system comprising two houses: a Senate consisting of 19 members and a House of Representatives with 39 members. Under the Spanish colonial government, Puerto Rico had a unicameral legislature, the House of Delegates of Puerto Rico.
The legislature was to be elected by manhood suffrage (limited at the time to white males) for a term of four years. Acts of the Legislature could be vetoed by the governor, but his veto could be overridden by a two-thirds vote, in which case the President of the United States would make the final decision.
Matters relating to franchises and concessions were vested in a Public Service Commission, consisting of the heads of the executive departments, the auditor, and two elected commissioners. A Resident Commissioner to the United States was elected by popular vote for a four-year term; the Resident Commissioner's duties included representing Puerto Rico in the U.S. House of Representatives, with a voice but without vote, as well as before the executive departments in Washington.
Under the Act, six executive departments were constituted: Justice, Finance, Interior, Education, Agriculture, Labor and Health. The governor, the attorney-general, and the commissioner of education were appointed by the President with the approval of the U.S. Senate; the heads of the remaining departments were appointed by the governor of Puerto Rico, subject to the approval of the Puerto Rican Senate.
The Governor of Puerto Rico was to be appointed by the President of the United States, not elected. All cabinet officials had to be approved by the United States Senate, and the United States Congress had the power to veto any law passed by the Puerto Rican Legislature. Washington maintained control over fiscal and economic matters and exercised authority over mail services, immigration, defense and other basic governmental matters. Puerto Rico was not given electoral votes in the election of U.S. President, because the Constitution of the United States of America allows only full-fledged states to have electoral votes.
Section 3 of the act also exempted Puerto Rican bonds from federal, state, and local taxes regardless of where the bond holder resides. [b] This has made Puerto Rican bonds extremely attractive to municipal investors as they may inure from holding a bond issued by a state or municipality different from the one where they reside. This is because municipal bonds that enjoy triple tax exemption are typically granted such exemption solely for bond holders that reside in the state that issues them.  
Before the Jones–Shafroth Act, insular Puerto Ricans were not citizens of the United States. Subsequent to the Act, they immediately became U.S. citizens. The act also extended almost all U.S. laws to have the same force and effect in Puerto Rico as in the United States (the only laws excepted were those concerning internal revenues) including the National Defense Act of 1916 which established the composition of the U.S. military. Two months after Congress passed the Jones–Shafroth Act, that same Congress enacted the Selective Service Act of 1917 which based conscription "upon liability to military service of all male citizens." Through its passage, the Jones–Shafroth Act—via a combination of citizenship and the expansion of U.S. laws to Puerto Rico, including the aforementioned National Defense Act—imposed mandatory conscription into the U.S. military on Puerto Ricans, precisely at the moment that the United States entered World War I. As a result, more than 18,000 Puerto Ricans served in the U.S. armed forces during World War I.
Portions of the Jones Act were superseded in 1948, after which the Governor was popularly elected. In 1948, U.S. Congress mandated Puerto Rico to draft its own Constitution which, when ratified by the electorate and implemented in 1952, provided greater autonomy as a Commonwealth.
- Pub.L. 81–600 "Except as provided in section 5 of this Act, the Act entitled "An Act to provide a civil government for Porto Rico, and for other purposes", approved March 2, 1917, as amended, is hereby continued in force and effect and may hereafter be cited as the "Puerto Rican Federal Relations Act"."
- Pub.L. 64–145 §3 "... all bonds issued by the government of Porto Rico, or by its authority, shall be exempt from taxation by the government of the United States, or by the government of Porto Rico or of any political or municipal subdivision thereof, or by any state, or by any county, municipality, or other municipal subdivision of any state or territory of the United States, or by the District of Columbia."
- Luis Muñoz Rivera
- Munoz Rivera, Luis (17 July 1859-15 Nov. 1916)[ permanent dead link]
- Glass, Andrew (March 2, 2008). "Puerto Ricans granted U.S. citizenship March 2, 1917". Politico.
- Hagerman, Frank (July 2004). "John Franklin Shafroth". The Colorado Lawyer. 33 (7): 15. Archived from the original on 2012-03-08. Retrieved 2013-06-16.
- [The Louisiana Purchase and American Expansion: 1803-1898. By Sanford Levinson and Bartholomew H. Sparrow. New York: Rowman and Littlefield Publishers. 2005. Page 166, 178.]" U.S. citizenship was extended to residents of Puerto Rico by virtue of the Jones Act, chap. 190, 39 Stat. 951 (1971) (codified at 48 U.S.C. § 731 (1987)")
- Moscoso, Guillermo (2002-03-11). "Puerto Rico: Myths About U.S. Citizenship". [The San Juan Star]. p. 20.
- http://www.municipalbonds.com/tax-education/tax-exemption-from-state-income-taxes. "As a general rule in most states, if the bonds are issued in a particular state, they are exempt from that state's income taxes."
- http://www.barrons.com/articles/SB50001424052748704836204578354303522222668 "Muni income generally escapes federal taxes, along with state taxes for those who buy bonds in their home states."
- Cabranes, Jose. Citizenship and the American Empire (1979) (legislative history of the statute, reprinted from the University of Pennsylvania Law Review).
- Gatell, Frank Otto. "The Art of the Possible: Luis Muñoz Rivera and the Puerto Rico Bill." Americas 1960 17(1): 1-20.
- Morales Carrion, Arturo . Puerto Rico: A Political and Cultural History (1984).
- Picó, Fernando. Historia general de Puerto Rico. Río Piedras: Ediciones Huracán, (1986).