JUDY WOODRUFF:

Joining me now to review today's announcement and the fight against the Islamic State are former U.S. Defense Secretary and CIA Director Leon Panetta, former commander in chief of U.S. Central Command, retired General Anthony Zinni, former Undersecretary of Policy at the Department of Defense Michele Flournoy, and retired U.S. Army Colonel Andrew Bacevich.

Welcome to all four of you.

Let me just quickly go around the group, to begin, and get your response to this addition of 450 more military advisers in Iraq.

Secretary Panetta, you first.

LEON PANETTA, Former Secretary of Defense: Well, there's no question that I think the president's taken the right step in adding these trainers and advisers.

We're in a tough situation there. ISIS, obviously, is resilient. They have got a lot of momentum. I think we need to do this. I suspect that we're going to have to take more steps, particularly that now that we're in a combat zone, where we're going to have to have more flexible rulings of engagement.

I think we do need additional special forms to help not only with C.T. operations, but with targeting. And I do think we have to ensure that arms do flow both to the Sunnis and the Kurds. All of that is going to be necessary in order to be able to achieve the mission that we have embarked on.