"You can't still think that going into Iraq, now, as a sane human being, was the right thing to do," Ingraham said on her radio show.
"If you do, there has to be something wrong with you," she added.
Bush made the remark in an interview set to air Monday night, after Fox News host Megyn Kelly asked him if he would have ordered the invasion of Iraq in 2003, "knowing what we know now."
"I would have," he said. "And so would have Hillary Clinton, just to remind everybody."
This did not fly with Ingraham.
"No Hillary wouldn't!" Ingraham said on Monday. "Hillary wouldn't authorize the war now, if she knew what she knows now."
At one point she began laughing, and doubted that Bush was "his own person" capable of breaking with his brother, President George W. Bush.
"That's just a fun hypothetical, but you have to say no to that!" she said.
The radio host said the exchange did not bode well for Bush if he were to secure the GOP nomination and face off against Clinton and the press.
"You have to have someone who says, look, I'm a Republican but I'm not an idiot! I'm not stupid!" she said. "I learn from the past and I improve myself."
Listen to the clip, courtesy of Media Matters: