Western governments have generally tried to contain genocide by appeasing its architects. But the sad record of the last century shows that the walls the United States tries to build around genocidal societies almost inevitably shatter.

When I became director of CIA, it was just clear to me intuitively, without a whole lot of science behind it, that we had expanded rapidly and inefficiently. So I arbitrarily picked a number, 10 percent, and I said over the next 12 months, we are going to reduce our reliance on contractors by 10 percent.

Citizens victimized by genocide or abandoned by the international community do not make good neighbors, as their thirst for vengeance, their irredentism and their acceptance of violence as a means of generating change can turn them into future threats.

While I knew that individuals had in history - and still could - make a difference, it seemed presumptuous - even pompous - to imagine that I could be part of it, that I could be one of them.

I like to think that as I get older I'm getting better at spending time with people who have qualities that make them worth spending time with.

In the '90s, there was scant presidential leadership and insufficient domestic political mobilization for foreign policy grounded in human rights.

Because it started as an offshoot of al Qaeda in Iraq, ISIL has long been subject to U.N. sanctions, and all countries have a legal obligation to freeze its assets and prohibit its business dealings. But countries around the world need to do more to make these sanctions work.

The way governments treat their own citizens matters; it matters because it can have a direct impact on international peace and security - and on our respective national security interests.

Half of Syria's refugees are children, and we know what can happen to children who grow to adulthood without hope or opportunity in refugee camps. The camps become fertile recruiting grounds for violent extremists.