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

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.

Banning the burkini doesn't produce terrorists. But it does make the people who are already alienated, who are already disenfranchised, I many cases, economically disenfranchised in a place like France in many of those neighborhoods, and make them say, ah, ISIS's message is true and real.

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.

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.

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're not going to have a perfect batting average and it's important that Americans understand that.