It was no by mere accident that the second half of the 20th century proved to be much better than the first. It happened mainly because in the period surrounding the end of World War II some remarkable world leaders, including great Americans, worked hard to create institutions in which different nations could cooperate for the common good. International cooperation is not a useless abstraction. It has been a powerful and tangible force driving global prosperity. Today the international system and its institutions are under unprecedented stress. …
