At the end of the Spanish-American Wa,under the terms of the Treaty of Paris (1898), Spain ceded the Philippines to the United States in exchange for 20 million United States dollars. When it became clear to the natives thet American forces intended to occupy and control the country, revolts broke out. At a constitutional convention held against the wishes of American authorities. Aguinaldo was declared President of the Philippines Rebublic. The US refused to recognize any Philippine right to self-government,and on February 4, 1899, Aguinaldo declared war against the Unites States for denying them independence. In the US, there was a movement to stop the war, some said that the US had no right to a land whose people wanted self-government.

Filipino and an increasing number of American historiansrefer to these hostilities as the Philippine-American War (1899-1913), and in 1999 the U.S. Library of Congress reclassofied its references to use this term. In 1901, Aguinaldo was captured and swore allegiance to the United States. A large American military force was needed to occupy the country, and would be regularly engaged in war,against Filipino rebels, for another decade. An estimated 250,000 Filipinos were killed by the U.S. Forces in the attempt to put down the forces favoring independence.

Some measures of Filipino self-rule were allowed, however. The first legislative assembly was elected in 1907. A bicameral legislature,largely under Philippine control, was established. A civil service was formed and was gradually taken over by the Filipinos, who had effectively gained control by the end of World War I.

In 1934, the American Tyding-McDuffie Act granted philippine independence by 1946. On May 14, 1935, an election to fill the newly created office of President of the Commonwealth of the Philippines was won by Manuel L. Quezon and a Filipino government was formed on the basis of the US Constitution.