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

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?

I think as we look at this problem of ISIS, it's more than just an army. It's also a fight about ideas. And we have got to dry up their recruiting. We have got to dry up their fundraising. The way we intend to do it is to humiliate them, to divorce them from any nation giving them protection, and humiliating their message of hatred, of violence. Anyone who kills women and children is not devout. They have - they cannot dress themselves up in false religious garb and say that somehow this message has dignity.

An untrained or uneducated Marine ... deployed to the combat zone is a bigger threat to mission accomplishment ... than the enemy.

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, that sort of thing.

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.

The United States has been essentially engaged in an ongoing war that most people date from 2001. That war has taken us to Afghanistan, to Iraq, in a lesser way to other countries - Libya, Somalia, Yemen.