We can put a stake through the heart of Islamic State as an army. We can put a stake through the heart of its leaders. You can take away its territory. But you can't put a stake through the heart of the ideas, of the ideology, that sadly, tragically, still has some attraction for some small numbers in the Islamic faith.

In counterinsurgency operations, the human terrain is the decisive terrain.

Iraq does have many, many different tensions.

The central problem in Syria is that Sunni Arabs will not be willing partners against the Islamic State unless we commit to protect them and the broader Syrian population against all enemies, not just ISIS.

When I was commander of Central Command, obviously we were very concerned about the developments in Yemen, the developments in Somalia and elsewhere, in Africa and so forth. But the al Qaeda senior leadership is under unprecedented pressure.