We do everything humanly possible, consistent with military necessity, taking many chances to avoid civilian casualties, at all costs.

2017 is going to be another tough year for the valiant Afghan Security Forces and the international troops who have stood and will continue to stand shoulder to shoulder with Afghanistan against terrorism.

Since 9/11 we've been engaged in wars around the world, and General [James] Mattis has been a leading battlefield commander in many of those theaters, including in the April 2004 siege of Fallujah, where the US Marines killed so many people that the municipal soccer stadium in the city had to be turned into a graveyard for the dead.

Anyone who kills women and children is not devout. ISIS cannot dress themselves up in false religious garb and say that somehow this message has dignity. We're going to strip them of any kind of legitimacy.

In this age, I don't care how tactically or operationally brilliant you are, if you cannot create harmony - even vicious harmony - on the battlefield based on trust across service lines, across coalition and national lines, and across civilian/military lines, you need to go home, because your leadership is obsolete. We have got to have officers who can create harmony across all those lines.

We have the most skillful, firecest, and certainly the most ethical ground forces in the world... I'm not saying we have to commit right now, but certainly don't pull it off the table.

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?