On March 2, 1917, President Woodrow Wilson
signed the Jones-Shafroth Act. This law gave Puerto Ricans U.S.
citizenship. The Jones Act separated the Executive, Judicial, and
Legislative branches of Puerto Rican government, provided civil
rights to the individual, and created a locally elected bicameral
legislature. The two houses were a Senate consisting of 19 members
and a 39-member House of Representatives. However, the Governor
and the President of the United States had the power to veto any
law passed by the legislature. Also, the United States Congress
had the power to stop any action taken by the legislature in Puerto
Rico. The U.S. maintained control over fiscal and economic matters
and exercised authority over mail services, immigration, defense
and other basic governmental matters.
Ref: Jones-Shafroth Act - The Library of Congress