Many Beltway Republicans miniaturize the problem this plan presents. Stating the obvious, they argue that our government cannot conceivably vet these immigrants. Therefore, the argument goes, we cannot figure out who is a legitimate refugee and who is an ISIS terrorist — like the suicide jihadist, believed to be from Syria, who recently entered Europe with the tide of immigrants and helped carry out last week’s attacks in Paris.

But identifying terrorists is not the half of it. The bigger challenge is the infiltration of a population of people schooled to resist assimilation. As I’ve explained a number of times, including in Islam and Free Speech (a Broadside published by Encounter Books after the Charlie Hebdo massacre), highly influential Islamic leaders are embarked on a conquest strategy referred to as “voluntary apartheid”: the establishment of sharia enclaves that would eventually merge into an Islamic state that dominates Europe and the United States.