One of the lessons we've learned from the last 25 years of terrorism is that groups that have safe havens are able to develop external attack capabilities in a way that groups that don't have safe havens are not. So we need to find a way to squeeze them significantly in their safe haven. Taking away territory that really matters to them is really, really important because it prevents them from focusing on external attacks.

One great lesson from history we need to keep on re-learning. It is that sometimes your adversaries tell you exactly what they're going to do. How many times did [Osama] bin Laden say prior to 9/11 that he was coming after the U.S.? ISIS made clear that when they established their caliphate in Iraq and Syria, they were coming after the United States too.

As far as Paris goes, we don't know for sure yet how these guys communicate among themselves and how they communicated back to the ISIS leadership in Iraq and Syria, but I'm fairly confident we're going to learn they used these encrypted communication applications that have commercial encryption and are extremely difficult for companies to break - and which the companies have made the decision not to produce a key for.

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.

Look at it from [Vladimir] Putin's perspective, right. He's a trained intelligence officer, worked for the KGB, very talented, manipulated people much smarter than Donald Trump. He played this perfectly, right. He saw that Donald Trump wanted to be complimented.

As the briefer, my job is to carry CIA`s best information and best analysis to the president of the United States and make sure he understands it.

The one thing that struck me right off the bat was what Donald Trump said about Benghazi.There is this view out there that [Hillary Clinton] lied about what caused the attack, that she said it was the video.