We cannot meet 21st Century challenges with a 20th Century bureaucracy.

[The White House staff] start bringing in their kids, who you think should be babies and now are in second grade or something, and you've watched them grow up. So I think what ends up happening is you end up maintaining those networks and those contacts, but the concentrated interactions and experience that you have here, I don't think, I don't expect you can duplicate anyplace else.

We are engaging in the diplomatic efforts that are required within Iraq among the Shia, the Sunni and the Kurd, among friends, like Egypt, and Turkey and Saudi Arabia, but also enemies like Iran and Syria. They have to have buy-in into that process.

As a practical matter, it is hard to think of any society in human history in which a majority population has said that as a consequence of historic wrongs, we are now going to take a big chunk of the nation's resources over a long period of time to make that right.

I will support Iraqis and Syrians fighting to reclaim their communities.

I think that what is true is that the Russians intended to meddle, and they meddled. And it could be another country in the future.

Climate change constitutes a serious threat to global security, an immediate risk to our national security, and, make no mistake, it will impact how our military defends our country.