The U.S. At War, All for One

Any attempt on the part of a non-American State against the integrity or inviolability of . . . an American State shall be considered as an act of aggression against the States which sign this declaration—Final Act & Convention, Second Meeting of American Foreign Ministers, Havana, July, 1940. (All 21 countries signed.)

This week hemisphere defense switched abruptly from theory to fact. When the U.S. was attacked, 20 neighbor nations, bound by convention and economic necessity, took spontaneous action ranging from expressions of sympathy to declarations of war. There was general...