Political progress will only take place if sufficient security exists.

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."

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.

In Afghanistan you are not rebuilding, you are building. There is very limited infrastructure and extreme terrain, with deserts in the south and mountains so high in some areas that helicopters don't even fly well at a certain altitude because the air becomes so thin. The country has a serious problem of illiteracy, especially after so many years of war and Taliban rule.

I think no commander ever is going to come out and say, 'I'm confident that we can do this.

When you enlisted into the armed forces you swore to support and defend a Constitution that did not yet fully apply to you. You chose to endure the same sacrifices as your fellow comrades in arms to preserve the freedom of a land that was not yet fully yours. You accepted that you might have to pay the ultimate price on behalf of a nation to which you did not fully belong. Now, you will officially become citizens of the United States, a country to which each of you has already borne true faith and allegiance in your hearts and your deeds.

US Ambassador to Iraq Ryan Crocker and I have repeatedly sought to emphasize that the progress in Iraq is fragile and also, possibly, reversible.