I will always be an advocate in terms of wars of necessity. I am just much more cautious on wars of choice.

I think when it comes to the issues, I'd advise him to stick to the script. But, I mean, Donald Trump is going to have some very tough conversations and he's going to be talking about some very tough and complicated issues in all of the places that he visits.I think anytime a president does things that are humanizing, I think it's - it's good.

Power... Military success is not sufficient to win: economic development, institution-building and the rule of law, promoting internal reconciliation, good governance, providing basic services to the people, training and equipping indigenous military and police forces, strategic communications, and more of these, along with security, are essential ingredients for long-term success.

I think in the policies that have been followed since the president Donald Trump came into office, there really hasn't been any slack cut for the Russians. And I think one of the things that has surprised people has been that the relationship between the United States and Russia has in fact deteriorated since the election.

On the foreign policy side, there's the risk of being too spontaneous and too disruptive where you end up doing more harm than damage. And figuring out that balance is where having strong people around you matters.

I think that Vladimir Putin is certainly getting a lot of publicity for what the Russians are doing. And I'm not sure that's unwelcome to him. I think this is a guy who saw the U.S. basically come out against him in his reelection campaign in 2012. He saw the U.S. being behind all of the color revolutions in Eastern Europe and in Georgia and Ukraine and so on. So his view is the West has been interfering in his politics for years.

What I know concerns me. What I don't know concerns me even more. What people aren't telling me worries me the most.