I don't have to negotiate an arms agreement with Great Britain or with France.

Evil does exist in the world. A non-violent movement could not have halted Hitler's armies. Negotiations cannot convince al Qaeda's leaders to lay down their arms. To say that force may sometimes be necessary is not a call to cynicism - it is a recognition of history; the imperfections of man and the limits of reason.

I think there are a whole host of things that are civil rights, and then there are other things - such as traditional marriage - that, I think, express a community's concern and regard for a particular institution.

As an elected official who comes from the African-American community, there are some similarities. You are always trying to reconcile your own personal biography and affiliations with the demands of the broader democracy. And you need to make sure you are representing everybody.

For the first time, preventing nuclear proliferation and nuclear terrorism is now at the top of America's nuclear agenda.

Now, as the world's largest economy and as the world's second largest emitter, America bears our responsibility to address climate change, and we intend to meet that responsibility.

The good news is that the Paris Agreement is not just a bilateral agreement between the United States and some other country. You have 200 countries who came together. It's an international agreement.