We must be honest in acknowledging that neither Germany nor the US has the luxury of assuming that we can skate by on half-measures in Afghanistan and Pakistan and not risk suffering the consequences.

I was working with a number of African heads of state. And after their initial surprise, I think many of them just treated me as they would anybody else. They had to deal with me as a representative of the United States of America, and the United States of America was too important to be dismissed or ignored on any grounds.

I may not be able to work for anybody else again. I may just have to work for myself.

Be who you are. If you spend all of your time worrying about how people view you, you will not be either faithful to yourself or effective in what you're trying to do.

It is manifestly in the interest of the United States to deal with the very real threat that climate change poses. And that's why President Obama has worked so hard to reduce our own emissions and to lead internationally in forging the Paris climate agreement.

I think it's very, very important that in foreign policy and national security decision making, as in any other realm, that there be a range of diversity that reflects the full complexity of America. We should draw on those experiences to inform our decision making.

It's in our interest to continue with the Paris Agreement and to deal with climate change as the real threat it actually is.