I know that they joined late in the war around 1917 and provided fresh troops for the exhausted Allies, but to me it seams as if they walked into the war, punched the stumbling Germany once knocking him out. Then they started dancing around and cheering that as if they single handedly won it. Sure they were effective in the Meuse-Argonne Offensive, but what else did they do?

Germany was suffering from the effects of internal political collapse late in the war, so my question is this: was the US really that important to winning the war, or was it just a matter of time until the Allies would be victorious?