You are part of the world's most feared and trusted force. Engage your brain before you engage your weapon.

A country that armed Stalin to defeat Hitler can certainly work alongside enemies of al-Qaida to defeat al-Qaida.

Ultimately, a real understanding of history means that we face NOTHING new under the sun.

North Korea is a direct threat to the United States. They have been very clear in their rhetoric we don't have to wait until they have an intercont- intercontinental ballistic missile with a nuclear weapon on it to say that now it's manifested completely.

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 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.

We do not draw red lines unless we intend to carry them out. We have made very clear that we are willing to work with China, and we believe China has tried to be helpful.