September 11 did not fundamentally change world politics. Instead, it exacerbated already existing tensions about how to implement post-cold war collective security rules. Using a rule-oriented constructivist theory of global security, I argue that the dominant post-cold war global security trend is the gradual construction of collective security rules, including rules punishing human rights abuses, terrorism, and proliferation of weapons of mass destruction. Using an interpretive method called dialogical analysis, I analyze the debate about intervention in Kosovo and argue that the recent conflict over intervention in Iraq revolves around similar claims about how to implement collective security rules. This analysis challenges arguments that September 11 ushered in a new era of world politics that necessarily justifies more aggressive, preemptive U.S. policies.I would like to thank Karin Fierke, Yale Ferguson, Gavan Duffy, and David Ahola for comments on earlier drafts, as well as Maximo Sanchez Pagano for research assistance. Any errors are my own.