But as is usually the case with the United States, business interests also supported annexation of the Philippines. While Wall Street and business insiders like Mark Hanna had originally opposed the war, they all argued for the annexation of the Philippines. The Philippines, they said, had a population of 7 million people, which was a sizeable new market for American manufactured goods. Also, following Mahan's theories, the Philippines would provide an American coaling station and naval base to protect US trade interests and maintain stability throughout Asian waters. With both the public and big business largely behind annexation, McKinley pushed for the acquisition of the Philippines.
One of the results of the Spanish-American War was that the Mahan's theories of the influence of sea power on history became generally accepted as correct. After the Spanish-American War, in which the US Navy had played such a decisive role and acquired the coaling stations to support a worldwide Navy, the US accelerated growth of the Navy under Elihu Root, secretary of the War Department. (Root also founded the War College.) Therefore, partially because of the Spanish-American War, the US commanded a stronger Navy for World War I (1914-1918) than it might otherwise have had. However, the Philippines, far away from the US, did prove to be an indefensible commitment and a military liability in World War II, when the Japanese quickly overran the island in 1942.