The FBI has revealed that at least 15 percent of the agency's terrorism investigations focus on immigrants who arrived as refugees, vetted by groups like the United Nations.

Out of more than 2,000 "violent extremist investigations," FBI Director Jim Comey, "about 300 of them are people who came to the United States as refugees."

The testimony was uncovered by the Center for Immigration Studies from the long session Comey had in the Senate last week to mostly discuss the 2016 presidential election.

Center Executive Director Mark Krikorian said that refugees can slide through the normal vetting process if they are from enemy countries like Syria and Iran that do not cooperate with the United States.

He also said that the FBI's numbers provide further proof for President Trump's travel ban from terrorist nations. He just blogged:

So 15 percent of the FBI's terrorism cases are refugees — far more than their share of the immigrant population, let alone the general population. And that denominator of 2,000 presumably includes people with no immigration nexus at all — skinheads, antifa, Klan, environmental and animal rights extremists, et al. So the refugee share of immigration-related terrorism investigations is more than 15 percent, perhaps much more.

This suggests that the president's temporary pause in travel from six terrorist-ridden Middle Eastern countries (the subject of appeals court proceedings today in Richmond) is almost beside the point. Better, tougher, more thorough vetting isn't likely to make any difference since refugees really are pretty thoroughly vetted. The problem is that vetting people from failed or enemy states is impossible.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com