How to distinguish the good migrants from the bad ones will be a concern when they come here….

The civil war in Syria has created a refugee crisis in the millions, overwhelming a number of European nations that are struggling to cope with the influx. While critics are accusing the U.S. of being slow to respond, this may be a good thing given what James Clapper, Director of National Intelligence, had to say on Wednesday about the Islamic State’s ability to infiltrate the crisis.

“As they descend on Europe, one of the obvious issues that we worry about, and in turn as we bring refugees into this country, is exactly what’s their background?” Clapper said at an annual intelligence conference. “We don’t obviously put it past the likes of ISIL to infiltrate operatives among these refugees.”

“That is a huge concern of ours,” he added.

While he added that U.S. authorities, who have so far allowed in fewer than 2,000 of Syria’s some 4 million refugees, have a “pretty aggressive” system for screening the backgrounds of those seeking entry into the United States, Mr. Clapper said he’s not so confident about the capabilities of some European nations.

He made the remarks during a wide ranging question-and-answer session that former ambassador and U.S. intelligence chief John Negroponte moderated at Wednesday’s conference sponsored by the Intelligence and National Security Alliance and the Armed Forces Electronics Communication Association.