Former aides to Presidents George W. Bush and Barack Obama sparred over whether each other were culpable for the rise of Islamic extremism in Iraq and Syria.
Karl Rove, former top adviser to Bush, and Marie Harf, former spokeswoman for Obama's state department, disagreed about which party was at fault.
Discussing the Syrian Civil War that she said will continue even after allied forces regained control of Raqqa, Syria - ISIS' proclaimed capital - Harf criticized Rove's former boss.
"ISIS would never have existed if its precursor hadn't been able to flourish after we invaded Iraq during the Bush administration," Harf said.
Later, Rove responded to Harf, calling her remark an "audacious swipe" at the 43rd president.
"I'm really taken aback by your audacious swipe, suggesting that Bush was responsible for Al Qaeda and ISIS," Rove said. "Islamic terrorism has been around for 20 years before he took office."
Rove pointed to the 1993 World Trade Center bombing as an example of pre-2000s Islamic terrorism.
Harf said she was accusing the Bush White House of allowing for the spread of terror rather than the rise of terror.
"ISIS actually started as AQI during the Bush administration," she said.
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