The United Nations turns 70 on Saturday. Its founders, rebuilding the world from the ruins of World War II, had lofty and probably unreasonable expectations for what it could accomplish.

President Harry Truman said it was “designed to make possible lasting freedom and independence for all its members.” Ralph Bunche, a Nobel Peace Prize winner who was involved in the U.N.’s creation declared that it represented “our one great hope for a peaceful and free world.”