After a US warship (the Maine) exploded in Havana harbor in 1898, the US declared war on Spain, and destroyed the Spanish fleet in the Battle of Manila Bay. After the war, the Spaniards gave up and the Philippines was taken over by the Americans. There they declared the "Benevolent Assimilation" of the islands as a territory of the United States, and as a Commonwealth in 1935.
you're right, but Philippines wasn't actually taken over, it was sold.
If you talking about the world war II, it is because the Philippines is the best place to put war bases to attack Hiroshima, Japan.If you are talking about now, it is for business purposes, vacation or leisure.