The essence of America - that which really unites us - is not ethnicity, or nationality or religion - it is an idea - and what an idea it is: That you can come from humble circumstances and do great things.

Power is nothing unless you can turn it into influence.

The United States has no credible evidence that Iraq moved weapons of mass destruction into Syria early last year before the U.S.-led war that drove Saddam Hussein from power.

I do have a favorite Zeppelin song, Larry, Black Dog.

I was born in segregated Birmingham, Alabama. I didn't have a white classmate till we moved to Denver.

What we will not wait for is that particular nexus of terrorism, weapons of mass destruction that is extremism, and the technology to come together in a way that is harmful to the United States.

Multilateral diplomacy is hard. It's slower, it's tougher, it's a bigger slog. I've learned that sometimes the things you'd most like to do something about, you really have difficulty unless the international community really mobilizes.