The unprecedented 11 September 2001 terrorist attacks in the United States caused massive casualties and damage, and ushered in an era of greater uncertainty. While a prompt and vigorous policy response helped limit the immediate economic impact of the aggression, the heightened terrorist threat has some long-lasting, if diffuse, macroeconomic repercussions. Three channels of influence are explored in this paper: shrinking insurance coverage stemming from the perception of greater risk, higher trade costs possibly affecting international trade, and stepped-up security spending partially rolling back the “peace dividend” of the 1990s. It is argued that, in the absence of new large-scale terrorist attacks, and provided terrorism risk is dealt with efficiently, the net long-run macroeconomic impact is probably tangible but limited ...