AdvertisementAt A Hefty Cost, World War I Made The U.S. A Major Military PowerApril 06, 2017Greg MyrefacebookEmailGen. John "Black Jack" Pershing visits Arlington National Cemetery in 1925. Pershing led the U.S. forces in World War I, the moment when the American military first displayed its might in a major foreign war. The U.S. military suffered heavy losses, but it also expanded dramatically, modernized and became more professional under Pershing's command. (Library of Congress)