Development is a lot cheaper than sending soldiers.

Well, I've ruffled a few feathers at all the institutions I've led. But I think that's part of leadership.

There will be boots on the ground if there's to be any hope of success in the strategy.

I think that Vladimir Putin has decided, in a very strategic way, to turn the tables and do everything in his power to, as we've described Russian elections as illegitimate, to try and communicate to the rest of the world that Western elections are illegitimate. And it's not just us, we know that now. It's Germany, it's France, it's a number of other countries.

I think in the context of senior government positions, I think an anecdote of what I told President-Elect Barack Obama when we had our first meeting. And I said, "You don't know me. Can you trust me? Why do you think you can trust me?" and so on. But at the end, I said, "You can count on me to be loyal to you. I will not leak. I will keep my disagreements with you private. And if I cannot be loyal, I'll leave." Loyalty means doing what you think is in the best interest of that person as well as the country.

We should never lose sight of the ethos that has made the Marine Corps - where 'every Marine is a rifleman' - one of America's cherished institutions and one of the world's most feared and respected fighting forces

Future U.S. political leaders – those for whom the Cold War was not the formative experience that it was for me – may not consider the return on America’s investment in NATO worth the cost.