Book excerpt: A defining feature of the post-Cold War international security environment has been that the United States, acting either alone or with allies and coalition partners, possessed the capability to impose its will on states, such as Serbia and Iraq under Saddam Hussein, that could be termed regional adversaries. We define this term to mean countries (1) that pursue policies that are at odds with the interests of the United States and its security partners and that run counter to broadly accepted norms of state behavior and (2) whose size and military forces are not of the first magnitude. 1 The category is useful as a means of distinguishing this group of states from larger, more powerful states, such as Russia, China, and India, which do not share their vulnerabilities to forcible intervention and which, for the present, at least, are pursuing policies vis- -vis the United States and its allies that are generally more cooperative than confrontational.