King asserts that "Most catastrophic military decisions are rooted in GroupThink" which is faulty, but still rational. The rationalist theory focused around bargaining is currently under debate. The Iraq War proved to be an anomaly that undercuts the validity of applying rationalist theory to some wars. The statistical analysis of war was pioneered by Lewis Fry Richardson following World War I. More recent databases of wars and armed conflict have been assembled by the Correlates of War Project, Peter Brecke and the Uppsala Conflict Data Program. The following subsections consider causes of war from system, societal, and individual levels of analysis. This kind of division was first proposed by Kenneth Waltz in "Man, the State, and War" and has been often used by political scientists since then. There are several different international relations theory schools. Supporters of realism in international relations argue that the motivation of states is the quest for security, and conflicts can arise from the inability to distinguish defense from offense, which is called the security dilemma. Within the realist school as represented by scholars such as Henry Kissinger and Hans Morgenthau, and the neorealist school represented by scholars such as Kenneth Waltz and John Mearsheimer, two main sub-theories are: The two theories are not mutually exclusive and may be used to explain disparate events according to the circumstance. Liberalism as it relates to international relations emphasizes factors such as trade, and its role in disincentivizing conflict which will damage economic relations. Realists respond that military force may sometimes be at least as effective as trade at achieving economic benefits, especially historically if not as much today. Furthermore, trade relations which result in a high level of dependency may escalate tensions and lead to conflict. Empirical data on the relationship of trade to peace are mixed, and moreover, some evidence suggests countries at war don't necessarily trade less with each other. These theories suggest differences in people's personalities, decision-making, emotions, belief systems, and biases are important in determining whether conflicts get out of hand. For instance, it has been proposed that conflict is modulated by bounded rationality and various cognitive biases, such as prospect theory. The morality of war has been the subject of debate for thousands of years. The two principal aspects of ethics in war, according to the just war theory, are "jus ad bellum" and "Jus in bello". "Jus ad bellum" (right to war), dictates which unfriendly acts and circumstances justify a proper authority in declaring war on another nation.