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.

A low-carbon, clean energy economy can be an engine of growth for decades to come.

Climate change is one of the issues I worry most about because its impacts are enormous. But they're gradual, they're not immediate.

When people see opportunity, when they have a sense of control of their own destiny, then they're less vulnerable to the propaganda and twisted ideologies that have been attracting young people - particularly being turbocharged through social media.

Granting such immunity undermines the constitutional protections Americans trust the Congress to protect.

Four years ago, I promised to end the war in Iraq. We did. I promised to refocus on the terrorists who actually attacked us on 9/11. We have. We've blunted the Taliban's momentum in Afghanistan, and in 2014, our longest war will be over. A new tower rises above the New York skyline, al Qaeda is on the path to defeat, and Osama bin Laden is dead.

Fighting for what you think is right is always worth it.