Seventy years ago, on March 1, 1945, Franklin Roosevelt assured a war-weary nation that a new era of international peace and democratic government was at hand. The accords signed just weeks earlier at the Yalta Conference, he told Congress, laid the foundation for postwar cooperation between the Soviet Union and the democratic West.

“Never before have the major Allies been more closely united—not only in their war aims but also in their peace aims,” Roosevelt said. He went on to predict “the end of the system of unilateral action, the exclusive alliances, the spheres of influence, the balances of power, and all the other expedients that have been tried for centuries—and have always failed.”