Answer:
RECRUITING
Step-by-step explanation:
Crucial to US involvement in the war was the massive domestic propaganda led by the Committee on Public Information overseen by George Wing. The campaign included tens of thousands of prominent government-elects who delivered carefully prepared war speeches at thousands of public gatherings. Other branches of government were involved in the action, and private retaliatory groups such as the American Protective League carried out repression against people who opposed the US entry into the war or were of German descent. Other forms of propaganda included films, photographs, large posters...
The United States has never formally been a member of the Allies, but they have become some sort of associated force. The US had a small army, but recruited four million soldiers, and in the summer of 1918 sent 10,000 fresh troops to France every day. Germany has recalculated, believing that the United States will need much more time to send forces to Europe, and that their arrival will be able to prevent the use of submarines.