Based on the historical record and current threat analysis of available evidence, some projections can be made about the next major terrorist attack in the U.S.
First, it is roughly 85% likely to be linked to some kind of religious extremism. Global jihadism (a type of Sunni Islamist extremism) has been the predominant ideological motivation in recent years, but there have been several (often ignored) Christian extremist attacks in the U.S. as well.
Second, it is approximately 96% likely that the next attack will have nothing at all do with immigration. In other words, a travel ban focused on persons from specific countries, or even giving special scrutiny to travelers of certain religions, would likely have little or no impact on preventing the next terrorist attack.
Third, based on what we know about terrorist targeting preferences, the next attack is 99% likely to take place in an urban area. We know that most terrorists prefer to attack public gathering spaces, public transportation, a hotel or office building, but the specific target(s) of the next attack could literally be anything that the terrorist views as being strategically valuable for achieving their objectives.
As a side note, it is interesting that most of the major urban areas in the U.S. did not vote for the current presidential administration. Perhaps this helps explain their focus on immigration policy as a major necessity for counterterrorism. Banning immigration from unpopular countries plays well to this administration’s support base, but the truth is only a small fraction of terrorist attacks in the U.S. have had anything to do with immigration.
If you want to do your own analysis on terrorist attack trends (including perpetrators, ideologies, locations, targeting, etc.), please see the Global Terrorism Database, at: http://www.start.umd.edu/gtd/
James J.F. Forest, Ph.D. is professor in the School of Criminology & Justice Studies at UMass Lowell, Visiting Professor at the Fletcher School of Law & Diplomacy, and Senior Fellow at the Joint Special Operations University. His latest book is Essentials of Counterterrorism (Praeger, 2016).