Why were the American troops desperately needed for the Allied Powers?
PLZ HEL

After the rupture of diplomatic relations with Germany on Feb. 3, 1917, events pushed the United States inexorably along the road to war. Using his authority as commander in chief, Wilson on March 9 ordered the arming of American merchant ships so that they could defend themselves against U-boat attacks. German submarines sank three U.S. merchant ships during March 16–18 with heavy loss of life. Supported by his Cabinet, by most newspapers, and by a large segment of public opinion, Wilson made the decision on March 20 for the United States to declare war on Germany, and on March 21 he called Congress to meet in special session on April 2. He delivered a ringing war message to that body, and the war resolution was approved by the Senate on April 3 and by the House of Representatives on April 6. The presidential declaration of war followed immediately.

the main objectives of the progressive movement were eliminating problems caused by industrialization, urbanization, immigration, and political corruption.