We shouldn't overdramatize the current disagreements with the Russians. They are real, but they're not really all that threatening. And the notion that we're moving back to some Cold War I think is really an exaggerated judgment.

America is the only superpower. But our leadership is being tested in the Middle East, and some of the things that we have done in the Middle East are contributing to a potential explosion region-wide. And if that explosion gets out of hand, we may end up being bogged down for many years to come in a conflict that will be profoundly damaging to our capacity to exercise our power, to address the problems implicit in this global awakening, and we may face a world in which much of the world turns away from us, seeks its own equilibrium, but probably slides into a growing chaos.

Acting alone in a world that's alive in political stirring is to condemn oneself to isolation and probably protracted warfare of the kind that can be dissipating.

Global stability - economic as well as political - is at risk.

I think if NATO haven't expanded, we would have a no-man's zone between the E.U. and NATO and Russia, and that would be very dangerous.

I think the United States is currently a kind of wonder - wonderland with the president Trump speaking on subjects of his choice, some of which are entertaining, but none of which are very strategically substantive.

I can't believe that the Russians really think they're more insecure because Estonia is in NATO. And we don't have forces poised in Estonia to attack Russia.