The 9/11 terrorist attacks have had profound effect on U.S. domestic and foreign security policy, leading to several expensive wars and the erosion of civil liberties (under the USA PATRIOT Act). We review evidence on political reactions to the 9/11 attacks and conclude that subjective reactions to terrorism played an important role in shaping support for national security policy in the wake of 9/11. Support for a strong national security policy was most pronounced among Americans who perceived the nation as a threat from terrorism and felt angry at terrorists. In contrast, Americans who were personally affected by the attacks were more likely to feel anxious about terrorism, and this anxiety translated into less support for overseas military action. In addition, Americans who felt insecure after the 9/11 attacks and perceived a high future threat of terrorism were more likely than others to support strong foreign and domestic national security policies. Overall, research on American political reactions to 9/11 suggests that support for a strong government response to terrorism is most likely when members of a population perceive a high risk of future terrorism and feel angry at terrorists. (Contains 7 footnotes and 1 table.)