Donald Trump told Time magazine earlier this week that Republican leaders are urging him to soften his tone, but he feels more comfortable in “attacking style.”

That was evident on Thursday, when Trump doubled down and tripled down on his claim that President Obama was “founder of ISIS” and Hillary Clinton its “co-founder.”

“ISIS is honoring President Obama,” Trump said Wednesday night. “He is the founder of ISIS … and I would say the co-founder is crooked Hillary Clinton.”

In an interview with conservative radio host Hugh Hewitt, the real estate mogul was given the chance to clarify his remarks.

“I know what you meant,” Hewitt said. “You meant that he created a vacuum, he lost the peace.”

“No, I meant he’s the founder of ISIS,” Trump responded. “I do.”

Trump’s comments have forced media outlets like CNN to fact-check them in real time. (CNN)

According to Max Boot, senior fellow for national security studies at the Council on Foreign Relations, Trump’s incendiary rhetoric is undercutting what could be an effective critique of the Obama administration’s record on terror.

“I think Donald Trump is basically delegitimizing all legitimate criticism of President Obama or his track record in office,” Boot told Yahoo Global News Anchor Katie Couric on Thursday afternoon. “I am somebody who has been critical of what President Obama has done in Iraq and Syria. He has left a vacuum of power that has allowed ISIS and Hezbollah and other radical groups to flourish.

“That is a legitimate criticism,” Boot continued. “What Trump is saying is not a legitimate criticism. What he is saying is just plain nuts.”

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Hewitt offered Trump a “lifeline,” Boot noted, but the Republican nominee defiantly rejected it.

Boot also scoffed at Trump’s assertion that ISIS reveres Obama.

“I’d love to see his evidence for that,” Boot said, “given the fact that President Obama is sending warplanes to bomb ISIS on a daily basis. I’m kind of guessing that ISIS does not actually revere the president.”

Boot added: “If anybody else would be saying this, you’d be saying, ‘Oh my goodness. How on earth could he possibly say this?’ But with Trump, it’s become pretty standard fare because almost every single day he comes out with some literally insane statement.”