Abstract

This article evaluates the claim that homegrown Islamist terrorism is a growing threat in the United States. The “threat” of homegrown terrorism is defined as an increase in the number of deaths within the United States perpetrated by American citizens or residents inspired by Islamic militant jihadist ideologies, but acting independently from established terrorist organizations. The author identifies three conditions that could produce a growing threat of this kind. These include (1) an increased incidence of the number of American Muslims initiating terrorist plots in the United States; (2) an increase in the efficacy and skill of aspiring militants, such that even if more plots are not initiated, more Americans will be harmed by those that are attempted; (3) an increase in the ability of militants to hide or conceal their terrorist activities, such that the activities of aspiring terrorists are less likely to be detected and foiled by arrests, resulting in a greater number of successfully executed attacks. Evidence in support of any of these conditions suggests the threat of homegrown terrorism is indeed growing.