I look forward to the Trump Administration’s plan to improve screening for terrorists in its 90-day window. Terrorist acts are extremely rare. There have only been five that killed at least 3 persons.
The Cato Institute’s late 2016 analysis of foreign terrorism risk in the U.S. scrutinizes the data from over a 40-year period. Between 1975 and 2015, its report (Table 2) says that for each of the following categories there was one known terrorist who got into the U.S. for every —
644,990 green card recipients
2.651,962 illegal entries
129,341,353 visa waiver program visitors
The Institute says that five events accounted for virtually all deaths. From 1975 through 2015, those 154 foreign-born terrorists murdered 3,024 people, 98.6 percent of whom were killed (2,983 victims) on September 11, 2001. The other 1.4% of murder victims were dispersed over the 41-year period, with two spikes in 1993 and 2015.
The spikes were produced by the 1993 World Trade Center bombing that killed 6 people and the combination of two 2015 incidents—the Chattanooga shooting on July 16, 2015, that killed 5 people and the San Bernardino attack on December 2, 2015, that killed 14 people. The 2013 Boston Marathon bombing killed 3 people. This leaves 16 others to be accounted for.