Nothing keeps me awake at night. I keep other people awake at night.

Nothing keeps me awake at night. I keep other people awake at night.

I think as we look at this problem of ISIS, it's more than just an army. It's also a fight about ideas. And we have got to dry up their recruiting. We have got to dry up their fundraising. The way we intend to do it is to humiliate them, to divorce them from any nation giving them protection, and humiliating their message of hatred, of violence. Anyone who kills women and children is not devout. They have - they cannot dress themselves up in false religious garb and say that somehow this message has dignity.

Since 9/11 we've been engaged in wars around the world, and General [James] Mattis has been a leading battlefield commander in many of those theaters, including in the April 2004 siege of Fallujah, where the US Marines killed so many people that the municipal soccer stadium in the city had to be turned into a graveyard for the dead.

I'm from the American West. We have forest fires out there. And some of the worst forest fires in our history, the most damage were caused when we pulled the fire crews off the line too early. And so we're going to have to continue to keep the pressure on the enemy - ISIS. There's no room for complacency on this.

The destruction that we have wreaked in the various theaters in which we've been engaged is really quite astonishing. But again, lethality, destruction, killing doesn't seem to achieve our objectives. So, my own sense is that a lack of lethality does not define the core problem.

Find the enemy that wants to end this experiment (in American democracy) and kill every one of them until they're so sick of the killing that they leave us and our freedoms intact.