The deceit of the Allies would have fateful consequences. Germany, even under Hitler, would never have risked invading France again if her rulers and her generals had known in advance that Britain and America would oppose it by military force. The U.S. Senate's rejection of the Treaty of Guarantee brought a certain responsibility on the United States for the subsequent course of events which pushed western Europe to the brink of destruction by Germany, though this was scarcely recognized in America. The Senate's action did not spare the American republic in the end. It only made the reconquest of western Europe from the Germans, when the Second World War came, infinitely more costly in American lives and treasure than it would have been had a President's word been honored in the first place by the Senate. The United States, supremely complacent in its shortsighted isolation, was lost as a factor in guarding the peace of Europe it had helped to win, and in which its fate would always be intertwined."
William L. Shirer