I've worked for four presidents, and I've concluded that almost nothing is inevitable. History is to a significant extent the result of the interaction of personalities and ideas. And so I don't believe war between the U.S. and China is in any way inevitable, and it's well within the province of diplomacy and statecraft to avoid it.

Some governments are prepared to give up elements of sovereignty to address the threat of global climate change.

If the president Donald Trump had connected the Jerusalem question to some other positions, linking it to Israeli and Palestinian behavior or putting the Jerusalem statement in a larger context of U.S. policy, it could have potentially advanced the peace process. But I don't see how singling it out might help.

I think it was going to be hard to work with Russians on Syria. There is some potential overlap between the U.S. and Russia in that the Russians don't want to see the Syria situation unravel to a point where they have to escalate their own involvement. But at the moment, I don't see the U.S. and Russia on the same page in Syria. Russia seems much more interested in consolidating government control over liberated areas. It seems to me that the U.S. and Russia are proving they can disagree for independent reasons in any number of theaters.

I've worked for four presidents, and I've concluded that almost nothing is inevitable. History is to a significant extent the result of the interaction of personalities and ideas. And so I don't believe war between the U.S. and China is in any way inevitable, and it's well within the province of diplomacy and statecraft to avoid it.

The U.S. position on Jerusalem was not the reason why there hasn't been progress towards peace. The reason is that both the Israeli government and the Palestinian leadership are divided. And there is an enormous gap between Israelis and Palestinians. To say that this decision is only recognizing reality, that Jerusalem is the actual capital of Israel - well, that's true. But it's a selective recognition of reality.

Well, we ought to make clear to everybody that the next Korean War, if one were ever to happen, is going to be the last Korean War because it's going to end with a unified peninsula, and it's go to be under Seoul, not Pyongyang.