Republic of the Philippines
Who & why: the United States grants full independence on 4 July 1946, honoring a commitment made in the 1934 Tydings–McDuffie Act, delayed by the war. The republic goes on to endure Ferdinand Marcos's martial-law dictatorship (1972–1981, with Marcos remaining in power until the 1986 "People Power" revolution) before returning to democratic rule.
What it represents: the same 1898 design — a white triangle for liberty, equality, and fraternity; a golden sun with eight rays for the first provinces to revolt; three stars for Luzon, Visayas, and Mindanao — now finally the flag of a fully sovereign state, blue stripe uppermost in peacetime.