Philippine Declaration of Independence
Following the end of World War II, the United States granted independence to the Philippines on 4 July 1946 via the Treaty of Manila. July 4 was observed in the Philippines as "Independence Day" until August 4, 1964 when, upon the advice of historians and the urging of nationalists, President Diosdado Macapagal signed into law Republic Act No. 4166 designating June 12 as the country's "Independence Day". June 12 had previously been observed as "Flag Day" and many government buildings are urged to display the Philippine Flag in their offices.
United States territorial acquisitions
Preparation for a fully sovereign state was interrupted by the Japanese occupation of the Philippines during World War II. The United States suffered a total of 62,514 casualties, including 13,973 deaths in its attempt to liberate the Philippines from Imperial Japanese rule during the hard-fought Philippines campaign from 1944–1945. Full independence came with the recognition of Philippine sovereignty by the U.S. in 1946.