How did the American entrance into World War One turn the tide for the Allies?

The U.S. troops arrived just in time to turn the tide of the war in favor of the Allies. ... The influx of fresh troops helped to boost the morale of the Allies and played a major role in the defeat of the Germans. Wilson's Fourteen Points. After entering the war, President Wilson issued his famous Fourteen Points.

l think both of above are eqally important.