Surveys levels of terrorism in the United States and concludes that there does not appear to be a major terrorist threat in the United States at the present time comparable to the level and persistence of the terrorist campaigns waged in Spain, Italy, or Northern Ireland during the 1970s. However, such politically motivated groups as the anti-Castro Cubans, Puerto Rican separatists, and Croatian separatists have claimed credit for significant bombings and assassinations in the United States over the past several decades. This level of political violence is likely to continue, whether it is generated by these groups or others organized around new social controversies, such as nuclear power.
Jenkins, Brian Michael, Terrorism in the United States. Santa Monica, CA: RAND Corporation, 1980. https://www.rand.org/pubs/papers/P6474.html. Also available in print form.
Jenkins, Brian Michael, Terrorism in the United States, Santa Monica, Calif.: RAND Corporation, P-6474, 1980. As of September 09, 2021: https://www.rand.org/pubs/papers/P6474.html