Rudy Giuliani roasted Bill Kristol after the “Never-Trump” Republican mocked him for dropping out of a 2000 race against Hillary Clinton despite his cancer treatment at the time.

President Donald Trump‘s personal attorney fired back at Kristol in an appearance on Eric Bolling‘s Sinclair show, “America This Week,” calling for him to “have a little decency” and to apologize.

Kristol accused Giuliani earlier this week of lacking the courage to face Clinton in New York’s 2000 U.S. Senate race, but as Bizpac Review reported, the neoconservative pundit and former editor-at-large of the now-defunct political magazine The Weekly Standard, left out a key fact in his tweet.

“Rudy plays a tough guy now, on Twitter,” Kristol tweeted. “But he didn’t have the guts to take on Hillary in 2000 for the New York Senate seat. When that race got tough, Rudy Giuliani got going. As bullies do when confronted by a stronger person.”

Rudy plays a tough guy now, on Twitter. But he didn’t have the guts to take on Hillary in 2000 for the New York Senate seat. When that race got tough, @RudyGiuliani got going. As bullies do when confronted by a stronger person. https://t.co/JWgKhuCDmE — Bill Kristol (@BillKristol) April 22, 2019

Kristol was raked over the coals on social media for ignoring the fact that Giuliani was diagnosed with prostate cancer at the time. Giuliani slammed Kristol on Thursday and said he “left out a fact, I call it deception — lying.”

“I don’t feel I have to defend my courage to that character,” he said, explaining why he really dropped out of the Senate race.

“I was being treated for prostate cancer from April until December of 2000, my father died of prostate cancer,” he said. “I had to go through six weeks of external radiation, I had to every day take a nap for two hours, I would get sick to my stomach at the most inappropriate times.”

The former New York City mayor announced his diagnosis during a news conference in 2000, explaining cancer and the treatment for it as the reason he was suspending his Senate campaign against Clinton. The now 74-year-old former U.S. Attorney for the Southern District of New York went on to beat the cancer and Clinton went on to secure the Senate seat where she served until 2009.

“I used to think the core of me was in politics, probably,” Giuliani told Bolling. “It isn’t. When you feel your mortality and your humanity you realize that, that the core of you is first of all being able to take care of your health.”

He went on to say he was “able to function as mayor because I had a great staff, I couldn’t possibly have run or I would’ve left the party down, I was very disappointed by that.”

“If that man doesn’t apologize, there’s nothing left of decency with him,” Giuliani said about Kristol.

“So when you go through cancer, Bill, you start casting stones at people, but until then, have a little decency,” he added.