"The Five" co-host Juan Williams slammed the "vile" and "un-American" chant directed at Rep. Ilhan Omar, D-Minn., during a rally on Wednesday night -- and offered his theory as to why President Trump denounced it.

During Trump's rally on Wednesday, supporters in attendance could be heard shouting "send her back" in reference to the Minnesota Democrat.

On Thursday, Trump said: "I was not happy with it, I disagree with it, but again I didn't say that, they did." He added he felt “a little bit badly” about the chant and said that he started speaking “very quickly” when it started, apparently to drown out the chant.

On "The Five," Williams posited a theory as to why the president distanced himself from the chant.

'SEND HER BACK' CHANT AT TRUMP RALLY PROMPTS OUTCRY; OMAR RESPONDS

"I think the reason that he spoke out today was because there were a number of Republicans in Congress who said to Vice President Pence and possibly directly to Mr. Trump, you know, 'Mr. President this is not who we are as the Republican Party,'" Williams said.

He also blasted the president's initial comments and argued that the denouncement served as an admission that his controversial comments and tweets in recent days were racist.

"This really is un-American that you would say to people... three of them born in America... all American citizens and all four members of Congress, not all socialist by the way, and to say to them 'go back,' you know, 'send them back,'" Williams argued.

"I think he's acknowledging this was a racist statement, a racist tweet."

Co-hosts Jesse Watters and Greg Gutfeld disagreed with Williams with Gutfeld pointing out that the situation was not something the president could control.

"Maybe he should've been faster and stopped that. Maybe he should have but he didn't," Gutfeld said.

"You can't answer to things that are out of your control."

Fox Business' Kennedy added that the president failed while delivering his message against his opponent and learned a lesson.

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"The problem is when your opponent becomes a victim you have failed. And that's what the president has to realize," Kennedy said.

"That is something that really cuts to the heart of a lot of people who came here and the president, I think, has learned a lesson and he needs to shut it down next time."