Well-known international groups such as Hamas, Hizballah , and the Palestine Islamic Jihad continue to express their opposition to the United States and retain the ability to strike with little warning. Most terrorist incidents in the United States involve individuals or small extremist groups that strike once and are quickly apprehended. A lack of popular support for terrorism and efficient law enforcement limits the number of repeat offenders. Because Americans have little sympathy for terrorists, virtually no domestic terrorists groups exist per se . What exists is an eclectic array of extremist organizations, which do not officially condone terrorism but may serve as breeding grounds for terrorist activities.
Extremist groups are organizations that Espouse supremacist causes.
Foster discrimination based on race, creed, color, gender, religion, or national origin. Advocate the use of force or violence, or otherwise engage in efforts to deprive individuals of their civil rights. These organizations range from militias to single-issue groups espousing specific causes. Although most individuals within these organizations live within the law, the common ingredients of terrorism such as zealotry for a particular cause or belief, dissatisfaction with the US Government, and skills with weapons or intelligence are often present. According to unofficial estimates, so-called patriotic organizations may number more than 800.