We've seen what violent regime change looks like in Libya and the kind of chaos that can be unleashed. And, indeed, the kind of misery that it enacts on its own people.

I think the President Donald Trump was quite clear in his statement that he made to the American people that Syria's continued violations of U.N. resolutions and previous agreements that Syria had entered into regarding the Chemical Weapons Accord would no longer be tolerated. I think we have stood by and watched multiple weapon - chemical weapons attacks by the Syrian regime under the leadership of Bashar al-Assad.

We're hopeful that Russia will choose to play a constructive role in supporting ceasefires through their own Astana talks, but also, ultimately, through Geneva. And if we can achieve ceasefires in zones of stabilization in Syria, then I believe we will have the conditions to begin a useful political process.

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.

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

We are making tremendous progress that ISIS really does present to the homeland and to other homelands of allies around the world.

People who speak up for freedom in regimes that are oppressive are often a threat.