Fox News contributor Marc Thiessen on Thursday said Donald Trump’s warning that donors to GOP primary rival Nikki Haley will now be “barred from the MAGA camp” shows the former president and current GOP front-runner “hasn’t learned any lessons from why he lost in 2020.”

“When he says, ‘Anyone who makes a contribution to ‘Birdbrain’ will be permanently banned from MAGA,’ does that apply to Haley voters too?” asked Thiessen, a chief speechwriter to President George W. Bush and now a columnist for The Washington Post.

Thiessen then drilled down into the data to explain why Trump’s current alienation of Haley supporters could backfire if and when, as is widely expected, she drops out of the race and Trump becomes the GOP’s presumptive nominee.

Trump lost to President Joe Biden in 2020 “because he lost 43,000 swing voters in three states and about 43,000 swing voters will decide this election next November,” Thiessen told “Special Report” host Bret Baier.

Trump has to win them over, the commentator continued. But “they are not MAGA. They are either Democrats or center-right Republicans who are not big fans of his. He’s got to win them over and expand his base and not shrink his base” as Republicans fear he is doing with his attacks on Haley voters.

“You don’t ban people from MAGA if you want to become president of the United States again,” he added.