Answer: drafting men into the army
Explanation:
When the United States entered the war, the combined strength of the regular army and National Guard was only 379,000; at the end, it would be 3.7 million. The need for such large numbers of troops forced Wilson to implement a military draft. Under the Selective Service Act of 1917, all men aged twenty-one to thirty (later, eighteen to forty-five) could be drafted for military service. All told, about 2 million mostly under-trained American troops crossed the Atlantic, and about 1.4 million saw at least some combat, including 42,000 African Americans.