Abstract : Of all the creatures of the earth, only two--ants and men-- make war, and only man feels the need to justify it. Over the last two thousand years, a set of criteria for judging whether a war is just or not has emerged, first in the Christian West but then with the spread of European culture and secularization, throughout much of the world. Although seldom formally invoked anymore, these criteria form a basis for international law and to a great degree have been integrated into the world's political psyche. This essay will apply the seven criteria for just war--jus ad bellum--to the US decision to go to war with Iraq in 1991 both to test whether the American decision met the criteria and to see if the criteria are still valid.