The job of the leader is to get the big ideas right.

US forces have been increased [in Afghanistan ] from some 21,000 to about 31,000 over the past two years and a number of coalition countries have also increased their forces, there still are not sufficient troops.

The Islamic State fighters in Mosul are dead men walking and I think they increasingly know it.

If you don't want to have to kill or capture every bad guy in the country, you have to reintegrate those who are willing to be reconciled and become part of the solution instead of a continued part of the problem. And then, above all, the resources.

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 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."

We obviously don't want to cause problems for the Afghan government, President Hamid Karzai and the Afghan people. In fact, we want them to support our efforts on their behalf and not see us as unwelcome occupiers.