What was the nature of the United States involvement and why was the Pacific Front so difficult?

it would be  

germany had to pay all damages related to the war.

and i think

germany had to take sole responsibility for the war.

jewish people, gypsies, and political opponents.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.