*Cracks knuckles* Alllllrighty. You want to know the main role of US soldiers in World War 1? Heheh. In short? To fight. Okay so here's the thing. Our doughboys were literally fresh off the boat in France ready to fight some tough, mean and experienced German Infantry. The USA was there to fight with a purpose. I mean seriously, the Zimmermann telegram really was a stupid move. To add to that, they were already killing US citizens in unrestricted submarine warfare. So, heading back to the topic. Sure they brought supplies, but these american doughboys? They are tough. They can fight VERY hard. Take a look at Belleau wood (Now Forest of the Marines). 2nd battle of the Marne. Or the Argonne offensive. From these battles came stories of Valor. Read through them will you? I can't hold your hand everywhere.