US had a bigger economy, size, industrial base, military and the unity of different races in defeating Germany. American secret codes were undecipherable by the Germans because they were in the Native American language. Even Hitler was worried about the American Industrial base. How American factories could produce tanks and airplanes in minutes. America through the lend lease program supported the European and Soviet war effort by providing them materials to make tank and airplanes. The US signed the Geneva Convention so Axis soldiers were willing to surrender because they knew they would be treated well and in the process were probably willing to give up military secrets (Prisoner's Dilemma).