I think continued actions by Bashar al-Assad clearly call into any question of him expecting to have any legitimacy to continue as the leader of Syria. With each of those actions, like attack with conventional weapons, barrel bombs and block humanitarian aid he really undermines his own legitimacy.

Russia and the USA are two largest nuclear powers in the world; it's a really important relationship. How do we start making this work? How do we live with one another? How do we work with one another? We simply have to find a way to go forward.

The increase in the greenhouse gas concentrations in the atmosphere are having an effect. Our ability to predict that effect is very limited.

I think the Russians have played now for some time the role of providing cover for Bashar al-Assad's behavior. The alternative explanation that the Russians put forth is simply not plausible.

I do not think Syria can achieve international recognition in the future - even if they work through a successful political process, you know, the international community simply is not going to accept a Syria led by the Assad regime.

President Xi Jinping clearly understands, and I think agrees, that the situation in North Korea has intensified and has reached a certain level of threat that action has to be taken. And, indeed, the Chinese, even themselves, have said that they do not believe the conditions are right to engage in discussions with the government in Pyongyang. And so what I think we're hopeful is that we can work together with the Chinese to change the conditions in the minds of the DPRK leadership.

I think the relationship between the USA and Russia is too important. And it's too important to not find a way to move forward.