We need additional funding for more U.S. combat brigades in Europe. NATO needs to continue to modernize. It is starting to show with the Russians but these exercises are central to show that the alliance is firm, especially as the E.U. starts to have some weakness on the economic front.

We have a Muslim population which is better off economically, better engaged, and less drawn to the fight in ISIS. But as we've seen in places like California and elsewhere, we still have a threat, even if smaller.

I don't think bulk data collection was an enormous factor here, because generally, that deals with overseas calls to the United States. But what bulk data collection did was make the process more efficient. So there were no silver bullets there.

They [ French] still have an open border in Europe. And they have a Europe which doesn't have an integrated intelligence system like we do in the United States.

I think we have started accelerating over the past years. It's a modernization of NATO. It's at air, it's at sea, it's undersea, it's in cyber. Estonia in 2007, hit by Russian cyber-attacks. So what you see there with those exercises are critical.

We need additional funding for more U.S. combat brigades in Europe. NATO needs to continue to modernize. It is starting to show with the Russians but these exercises are central to show that the alliance is firm, especially as the E.U. starts to have some weakness on the economic front.

You've got a huge American population, you've got a small, small, small subset that is radicalized, and you have an even smaller subset that actually takes action. And you can't cover everyone who has some contact, someone bad. What you need is offense overseas, defense at home with intelligence and law enforcement, and really deep engagement with these communities.