(NewsNation) — Why hasn’t Donald Trump taken the advice of Bill O’Reilly and others to add more charm to his campaign?

O’Reilly said former President Donald Trump is a “man who does what he wants to do.”

“He doesn’t do the adviser thing,” O’Reilly said Tuesday on NewsNation’s “On Balance.” “I mean, he has people giving suggestions, but Trump is spontaneous. … But Trump is a good presenter. People like to watch him in action, and I think he should use some of that, rather than be vitriolic.”

This week, Trump insisted he has to insult Vice President Kamala Harris despite admitting that doing so might hurt him in the 2024 election.

“I have to do that,” Trump told CBS, when asked whether he thinks attacking the vice president’s intellect is an effective message on the campaign trail. “I don’t consider that an insult — I consider that a fact.”

“Well, I don’t think she’s a very bright person. I do feel that. I mean, I think that’s right. I think I am a very bright person, and a lot of people say that,” he said in the interview. “I don’t think she’s a very bright person. And you know what? Our country needs a very smart person, and I don’t think she’s a very smart person.”