The weakness of international law governing the use of military force goes back to the signing of the U.N. Charter in 1945. The founders understood that a simple rule prohibiting the use of military force except in self-defense, or with the consent of another state, would not be adequate for regulating war. But they could not draft a code complex enough to anticipate all the contingencies that might justify war. Instead they set up the Security Council and reasoned that this body could determine when war might be justified for purposes other than self-defense. But the Security Council was frozen first by the Cold War rivalry between the United States and the Soviet Union, and then the cold peace rivalries between the United States, Russia, and China. It has authorized only two wars since its inception (the Korean War and the first Iraq War; it also retroactively approved the U.S. invasion of Afghanistan in 2001).