I think the core problem is much closer to recognizing where force is of value, where it is useful, and to distinguish that from situations in which war is not useful or is indeed counterproductive.

When you're in operations, the best thing you can do at the top level is get the strategy right. You have to get the big ideas right, you have to determine what is the policy, what is the level of effort you're willing to commit to it? And then you delegate to those who have to execute that strategy to the appropriate level. What's the appropriate level? It's the level where people are trained and equipped to take decisions so we move swiftly against the enemy.

You are part of the world's most feared and trusted force. Engage your brain before you engage your weapon.

I was struck by the fact that none of the senators, basically, asked General [James] Mattis, "Well, General, how is it that we haven't won?" We haven't won anywhere, 'winning' in the sense of conclusively achieving our political objectives, however you might want to define those objectives.

Yousef Aid Ahmed has memorized the places where his four brothers' bodies laid after they were killed by US marines, he said. The family recounts that November day in 2005 and says it was a massacre of the brothers, along with 20 other people, following a roadside bomb in Haditha.

If in order to kill the enemy you have to kill an innocent, don't take the shot. Don't create more enemies than you take out by some immoral act.

Our strategy right now is to accelerate the campaign against ISIS. It is a threat to all civilized nations.