It's probably a prerequisite for the job, or at least you have to have enough craziness to think that you can do the job. I think that [Donald Trump] has not spent a lot of time sweating the details of, you know, all the policies.

I wonder, sometimes, whether men and women in fact are capable of learning from history--whether we progress from one stage to the next in an upward course or whether we just ride the cycles of boom and bust, war and peace, ascent and decline.

We don't have this huge footprint, we are less likely to be targeted as, you know, occupiers [in Afghanistan and Iraq].

I would have I think made a bigger mistake if I had said, "Eh, chemical weapons. That doesn't really change my calculus." I think it was important for me as president of the United States to send a message that in fact there is something different about chemical weapons [in Syria].

Even limited military actions end up carrying with them great costs and unintended consequences.

At a time when the European project is facing challenges, it's especially important to show the benefits of economic integration by continuing to invest in our people and working to reduce inequality, both within and across our countries.

What makes [cyber security] difficult is because it's not just a government problem. It is a private sector and government problem. And there's gotta be a lot more cooperation.