The question was what if we leave Iraq and al-Qaida resurges:
"If al-Qaeda is forming a base in Iraq then we will have to act in a way that secures the American homeland and our interests abroad," said Senator Barack Obama (D) Illinois.
On Wednesday, John McCain jumped on that answer.
"He would send military troops if al-Qaida established a base in Iraq. I have some news al-Qaida is in Iraq, it is called al-Qaida in Iraq," said Senator John McCain (D) Arizona.
And Barack Obama responded.
"I have some news for John McCain and that is there was no such thing as al-Qaida in Iraq until George Bush and john McCain decided to invade Iraq," said Senator Obama.
At Stanford's Hoover Institution, Professor Larry Diamond is an expert on the Iraq conflict and a former advisor to the coalition forces.
"Obama is certainly right that al-Qaida was not in Iraq until the united states invaded occupied the country and drew it in like a magnet," said Hoover Institution Professor Larry Diamond, Ph.D. "But it's also true that once they were there they became a phenomenon that wasn't simply going to go away merely by the united states leaving, in fact it could've gotten worse."
Diamond believes both candidates go too far. He says McCain's committeemen to stay until the job is done will lead to further corruption and inaction by the Iraqi government.
And Obama's commitment to begin withdrawing troops is too fixed and too rapid.
One way to get out without Iraq blowing up in our faces is a much more flexible timetable -- one that isn't publicly disclosed.
"And that's part of a process of very sophisticated very hard edged and very multilateral bargaining with all of the different Iraqi groups," said Professor Diamond.
Politically john McCain is going after Barack Obama, for a reason.
Today a poll by the L.A. Times shows Barack Obama has a six point lead over Hillary Clinton nationwide.
And in Pennsylvania two weeks ago, she had a 16 point lead over Obama. Today that lead has shrunk, from 16 points down to six points -- a ten point drop in a little under two weeks.
Hillary Clinton's poll numbers continue to drop, and she's running out of time.