How important were American troops in WW1?

Aside from the financial, industrial, and manpower advantage already cited by Andrei Botu that the USA provided to the Allies, the Americans provided a doctrinal and proficiency advantage that revitalized Allied infantry tactics and caught the Germans by surprise. read more

US troops in WWI were very important because they came in as a surprise that uppended the German plans. Germany was looking at the US as a pushover since the US had a regular army of only about 100,000 people. The Germans decided that with or without US they would be in the same situation so they started a pretty aggressive submarine war with the US. read more

Since the transport ships needed to bring American troops to Europe were scarce at the beginning, the U.S. Army pressed into service passenger liners, seized German ships, and borrowed Allied ships to transport American soldiers from ports in New York City, New Jersey, and Virginia. read more