You have to have a military and intelligence approach to removing leadership that results in rapid frequent removals from the battlefield. It's got to be one, two a week, not just one or two every three or four months.

I'm concerned, too, about ISIS' ability, right, to infiltrate people. But we have got some very effective, robust processes for vetting people. We brought in thousands of Iraqi refugees after the Iraq War. Not a single one has ever turned out to be a terrorist because the vetting was so good.

I want the vetting to be solid. But I also want to bring these people in because not bringing them in sends a message, right, to the Muslim world and plays into the ISIS narrative and the Al Qaeda narrative, right, that this is a war between religions. And we can't have that.

The [Edward] Snowden disclosures created this perception that people's privacy was being put at significant risk.

From Mr. [Donald] Trump's perspective, right, he simply heard [Vladimir] Putin compliment him. He then responded by complimenting him. He never thought that he might be being played.

I worked with [Hillary Clinton] for four years very closely when she was secretary of state and I was at the CIA. I provided her - personally provided her some of the most sensitive information that the Central Intelligence Agency has.

ISIS went to school on how we were collecting intelligence on terrorist organizations by using telecommunications technologies. And when they learned that from the [Edward] Snowden disclosures, they were able to adapt to it and essentially go silent.