The long-run trend in the decline of interstate war is notable. Once a common feature of all civilizations and geographical areas, the world since 1945 has featured a very low probability that two or more states would resolve their conflicting interests by armed conflict. The probability that in any given year war between states will occur has declined to less than one percent. This pattern contrasts with the prevalence of domestic violence since 1945. Wars within states have made up the vast majority of armed conflicts, but our models of International Politics have little to say about them. But the benign International situation of the post Cold War era has begun to crumble. The Russian attack on the Ukraine, tensions over Taiwan, the lapse of arms control agreements, the arms build-up of China and India are indicators of increased dangers and greater probabilities of armed conflicts between states. Cyber wars, as between Israel and Iran, have also appeared. The certainties of the Cold War era have been replaced by uncertainties and higher risks.