Why was it a bad idea for America to join World War 1?
It was bad idea for America to join World War 1 because of the impending war spending that would severely damage the economy. Also, the loss of men to war casualties would lead to labor unrest.
America never joined/allied with Germany in World War I and II. America was an ally and Germany was an axis. But America did join partially because of Germany. Germany announced that they would use their submarines on anyone and America felt threatened and decided they needed to take action. Germany also contacted Mexico and asked Mexico to help Germany defeat America.