The importance of strengthening Euro-Atlantic security: the growing dangers pile pressure on our rules-based international system, so we need to do more to strengthen NATO, the bedrock of our defense - not just upping spending, but making the alliance more agile and more capable of tackling dangers from all directions.

It is mostly a matter of wills. Whose will is going to break first? Ours or the enemy's?

I would consider the principal threats to start with Russia. And it would certainly include any nations that are looking to intimidate nations around their periphery, regional nations nearby them, whether it be with weapons of mass destruction or I would call it unusual, unorthodox means of intimidating them.

I'm from the American West. We have forest fires out there. And some of the worst forest fires in our history, the most damage were caused when we pulled the fire crews off the line too early. And so we're going to have to continue to keep the pressure on the enemy - ISIS. There's no room for complacency on this.

General [James] Mattis's primary experience - indeed, his only experience - is as a member of the United States Marine Corps, where he served for 41 years. That's his experience.

What would you do differently as defense secretary to compensate for this record in which the greatest military in the world, as we are constantly told, doesn't get the job done?

You've been told that you're broken. That you're damaged goods ... there is also Post-Traumatic Growth. You come back from war stronger and more sure of who you are.