The United Nations offers international legitimacy in what we might do.

I think that before you take on nation building in your mind's eye as to how it should be, you'd better have a clear understanding if this is doable and will work.

I think the Mogadishu effect, if I had to define it, is we need to be more careful where we decide to commit US forces, and for what reason, and to make a clear judgment as to what we can and can't do and whether it's in our interests, or we could afford the resources that it would take to make the situation right.

Service rivalry leads to service pride, which is good for building morale and esprit.

We will pay for this [climate change] one way or another. We will pay to reduce greenhouse-gas emissions today and we'll have to take an enormous hit of some kind. Or we will pay the price later in military terms. And that will involve human lives. There will be a human toll. There is no way out of this that does not have real costs attached to it.

You have to give everybody another recourse as some means other than violence, no matter how distasteful it may be to have to deal with them and what they represent.

Yet, here we are, long and difficult years into that conflict, ... we still have not created the state we promised them. On the contrary, our costly and valiant efforts have produced an outcome our government did not predict or intend-a failed state spinning out of control into anarchy and civil war.

If you put two brigades on the ground right now with U.S. forces, they would push ISIS back into Syria in a heartbeat.