People often ask, why aren't you reading about what it is you're working on right now? And the truth is, you only get three pages a night before your eyelids close.

If you look at casualties, you find countries that had much higher loss rates per capita than the US. Denmark comes to mind, the United Kingdom, they have suffered heavy losses at various points, the Germans as well.

The president and I sat down in the Oval Office, and he expressed very clearly that what he wants from me is my best professional military advice.

President Obama has said that our aspirations should be realistic. We are not going to turn one of the poorest countries in the world, that was plunged into 30 years of war, into an advanced, industrialized, Western-style democracy. What we want to achieve is Afghanistan's capacity to secure and govern itself.

Every civilian's death diminishes us, collectively.

The task [in Afghanistan] is to reduce civilian casualties while still not hesitating to respond to enemies who are trying to kill our soldiers.

I did a week-long assessment in 2005 at (then Defense Secretary Donald) Rumsfeld's request. Following our return, I told him that Afghanistan was going to be the longest campaign of what we then termed "the long war."