Scarborough made the announcement in an appearance Tuesday night on "Late Night With Stephen Colbert" along with Mika Brzezinski, his co-host and fiancee.
On the show, the conservative pundit criticized President Donald Trump for his Muslim ban and his claims not to know who David Duke is and what the Ku Klux Klan does. He also criticized members of the Republican Party for not repudiating Trump's positions.
"Time and time and time again they turned the other way," Scarborough said. "And they're doing the same thing now. And it's actually disgusting. And you have to ask yourself, 'What exactly is the Republican Party willing to do? How far are they willing to go? How much of this country and our values are they willing to sell out?'"
Colbert then asked Scarborough, "But aren't you a Republican?"
"I am a Republican, but I'm not going to be a Republican anymore," Scarborough told Colbert. "I've got to become an independent." His announcement was met with big applause.
It wasn't the first time Scarborough called out the president. He and Brzezinski became embroiled in a battle with Trump last month after the president dragged them on Twitter.
"I heard poorly rated 'Morning Joe' speaks badly of me (don't watch anymore). Then how come low I.Q. Crazy Mika, along with Psycho Joe, came to Mar-a-Lago 3 nights in a row around New Year's Eve, and insisted on joining me. She was bleeding badly from a face-lift. I said no!" Trump said via Twitter, drawing criticism from politicians on both sides of the aisle.
In an op-ed headlined "Donald Trump is not well" in the Washington Post, the two morning talk show co-hosts denied Trump's claims about the visit to Mar-a-Lago and said Brzezinski did not have a facelift but had her chin tweaked.
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