In the past, there have been a range of treaties that divided Congress and every administration was able to get them through.

I don't regret at all saying that if I saw Bashar al-Assad using chemical weapons on his people that that would change my assessments in terms of what we were or were not willing to do in Syria.

As the world's largest economy and second-largest carbon emitter, as a country with unsurpassed ability to drive innovation and scientific breakthroughs, as the country that people around the world continue to look to in times of crisis, we've got a vital role to play. We can't stand on the sidelines. We've got a unique responsibility.

I think that when it comes to Social Security, all of us want to make sure that our senior citizens can retire with dignity and respect. And everybody has to be open-minded in thinking how do we firm up a system that, in fact, is going to be in difficulty in the coming years.

Hope is not blind optimism. It's not ignoring the enormity of the task ahead or the roadblocks that stand in our path. It's not sitting on the sidelines or shirking from a fight. Hope is that thing inside us that insists, despite all evidence to the contrary, that something better awaits us if we have the courage to reach for it, and to work for it, and to fight for it. Hope is the belief that destiny will not be written for us, but by us, by the men and women who are not content to settle for the world as it is, who have the courage to remake the world as it should be.

Americans... still believe in an America where anything's possible - they just don't think their leaders do.

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.