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.

The thing we've learned from the last 20 years of counterterrorism is the significant value you get from removing leadership from the battlefield in degrading the organization.

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.

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

If you were watching CNN, they were saying the NSA is listening to your phone calls. It's reading your emails. When you call your grandma in Arkansas, the NSA knows. All total bulls - t. They made the public more concerned about the privacy issue than the legitimate facts should have done.

Donald Trump didn't even understand, right, that [Vladimir] Putin was playing him. So, in Putin's mind, I have no doubt that Putin thinks that he's an unwitting agent of the Russian Federation, although Putin would never say that.

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.