Democratic presidential candidates faced off Saturday during a debate in Iowa, the day after the attacks in Paris. Vermont Senator Bernie Sanders criticized former Secretary of State Hillary Clinton’s 2002 Senate vote in support of the Iraq War, saying the “disastrous invasion of Iraq,” which Sanders opposed, led to the rise of ISIL. Meanwhile, Hillary Clinton invoked 9/11 to defend herself against Sanders’ criticism of her Wall Street ties.

Sen. Bernie Sanders: “Why do—why, over her political career, has Wall Street been a major—the major campaign contributor to Hillary Clinton? Now, maybe they’re dumb, and they don’t know what they’re going to get, but I don’t think so.”

Hillary Clinton: “I represented New York, and I represented New York on 9/11, when we were attacked. Where were we attacked? We were attacked in downtown Manhattan, where Wall Street is. I did spend a whole lot of time and effort helping them rebuild. That was good for New York. It was good for the economy. And it was a way to rebuke the terrorists who had attacked our country.”

Clinton’s reference to 9/11 in response to criticism of Wall Street donations led to widespread criticism on social media. In a Twitter post read aloud by moderators during the debate, one user wrote: “Have never seen a candidate invoke 9/11 to justify millions of Wall Street donations. Until now.”