When you do have really tapped out resources that cover so many investigations, it can help you move through and discard some faster.

I think the refugee problem is Europe is vastly worse than we have in the United States.

You have the intelligence front and the engagement front. On the intelligence front, the French are better than many of their European counterparts. But they are really challenged in two specific ways.

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.

We can't be French and Muslim at the same time. And that's exactly what ISIS wants that population to think.

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.

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.