Homegrown terrorism; the known unknown

Homegrown terrorism has attracted significant attention following the 2004 Madrid and 2005 London bombings. Homegrown terrorism is usually thought to be a new phenomenon, with few observed events, and inherently distinct from transnational terrorism or the old domestic terrorism in Europe. However, little research has so far examined the alleged distinctiveness of homegrown terrorism empirically. I argue that homegrown terrorism shares many similarities with domestic and international terrorism, suggesting that we can learn more about homegrown terrorism from studying these similarities rather than insisting on its inherent distinctiveness. I formulate these claims as testable hypotheses, which I examine using the ITERATE data on international and the TWEED on domestic terrorism, and compare these with information on homegrown terrorism. My findings suggest that homegrown terrorism follows the same logic of other types of domestic terrorisms, hence lessons can be learned through observations on domestic typologies. Homegrown terrorism is a separate strain of domestic terrorism due to ideological character of political Islam, yet differing from international terrorism in targeting patterns. The implications of the study are that counterterrorism efforts for homegrown terrorism should resemble those of domestic terrorism rather than international terrorism.