Peter Hasson joined Tucker Carlson to talk about former Vice President Joe Biden’s claim that his gaffes could be attributed to his childhood stutter.

Hasson, investigative editor at the Daily Caller News Foundation, has struggled with a stutter himself and noted that, while it has certainly made speech difficult at times, it has never caused him to invent experiences he never had. (RELATED: ‘I Have Traces Of This Myself’: Brit Hume Says It’s Clear That Biden Is Slipping)

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Carlson began by saying that Biden’s camp had often claimed that his “gaffes are simply a byproduct of a stuttering problem. Of course, a stutter does not explain why Biden is threatening to slap voters. It also doesn’t explain his sudden claim that he was arrested in South Africa,” Carlson continued. He then introduced Hasson to address the topic.

“Yeah, Tucker, this is honestly the most dishonest defense of Joe Biden that we’ve seen so far in this campaign,” Hasson said. “The idea that a childhood stutter is the reason why he is now confusing people and events from decades apart is nonsensical. As you were saying, I grew up with a stutter. I still work at it every day to be able to talk like a normal person.”

Hasson went on to list several of Biden’s gaffes, explaining, “I will be the first person to say that Joe Biden’s childhood stutter has nothing to do with him apparently convincing himself that he was arrested in South Africa trying to see Nelson Mandela. His childhood stutter has nothing to do with the fact that he keeps confusing female world leaders with Margaret Thatcher, who passed away seven years ago and left office thirty years ago — a childhood stutter has nothing to do with that. Nothing to do with the fact that just yesterday Joe Biden threatened to slap a factory worker in the face after he challenged him on gun rights.”

Hasson concluded that the real problem would be if and when Biden got to the general election, adding, “The people backing Joe Biden for president are now having to come to terms with the fact that his mental fitness is going to be challenged, is going to be much more greatly challenged in the general election than in the primary. President Donald Trump, as we all know, is not going to give Joe Biden a pass on his mental fitness the way that Bernie Sanders has given Joe Biden a pass on his mental fitness. It’s not going to go away.”

Carlson then asked whether Hasson found it offensive that Biden would use his stutter as an excuse for such things.

“Yeah, I mean, it’s generally laughable and personally offensive. The idea that if you have trouble pronouncing certain words or if you have issues with your breathing, that you therefore are liable to delude yourself into having exploits in South Africa that you never had,” Hasson said. “It’s insulting. It’s implying that it’s not a speech problem but a brain problem. That’s not the case.”

Carlson laughed and then asked one final question. “Really quick, I just want to check your credibility. Have you ever been arrested with Nelson Mandela?” he smiled.

“I’ve never been arrested with Nelson Mandela,” Hasson confirmed. “I guess that makes me the only stuttering person not to think that.”