ISIS seized a third of Iraq that the U.S. secured with ten years of sacrifice. In an interview for 60 Minutes, Former Secretary of Defense Leon Panetta said ISIS flourished because the U.S. got involved in Syria too late and left Iraq too soon. On the 47th season premiere Sunday, "60 Minutes" will report from Iraq and Syria on ISIS -- what it is, what it wants, and how to defeat it.

Former Secretary of Defense Leon Panetta weighs in on why he thinks ISIS was able to flourish.



Pelley: Back when you watched the stars and stripes being lowered for the last time in Baghdad, were you confident in that moment that pulling out was the right thing to do?

Panetta: No, I wasn't. I really thought that it was important for us to maintain a presence in Iraq.

But the elected Prime Minister, Nouri Al-Maliki didn't want the U.S. force. As Iraq moved on, on its own, civil war broke out in Syria. The U.S. stayed largely on the sidelines but Panetta says the national security team urged the president to do more.

Panetta: The real key was how can we develop a leadership group among the opposition that would be able to take control. And my view was to have leverage to do that, we would have to provide the weapons and the training in order for them to really be willing to work with us in that effort.

Pelley: But with virtually his entire national security team unanimous on this, that's not the decision the president made.

Panetta: I think the president's concern, and I understand it, was that he had a fear that if we started providing weapons, we wouldn't know where those weapons would wind up... My view was, "You have to begin somewhere."