[General James Mattis] said, reading allows you to learn from other people's mistakes without filling body bags with the bodies of your soldiers as you learn on the battlefield.

[ General James Mattis] is a Marine's Marine who has served in combat in both Afghanistan and Iraq.

Certainly, we shouldn't go about making a habit of taking generals and making them secretary of defense.

Why do soldiers fight? They join because they believe in a higher cause -- protecting religion, their nation, defending against a foreign nation. But why do soldier stay and fight? Soldiers aren't individuals. They are part of a unit. And that unit is led by a commander. If they don't trust their commander ... if there is no leadership, there is nothing.

t I think what [James Mattis] will do with the deal is monitor it very, very carefully and make sure that Iran is complying with every stipulation of it.

Michele Flournoy, by the way, is not just a talented and bright person. She was Hillary Clinton's secretary of defense in-waiting. So for her to give General [James] Mattis her support, that says something significant.

[General James Mattis] a very talented individual. He's - has a personal library of about 10,000 books and he's read most of them on military history and strategy and so forth.