The populists!
By 
The new, working class core of Republican Party had multiple demands on Kevin McCarthy, and one of them is to vote on a massive tax increase on the working and middle class, to fund a massive tax cut for the upper class:
As part of his deal to become House speaker, Kevin McCarthy reportedly promised his party’s conservative hardliners a vote on legislation that would scrap the entire American tax code and replace it with a jumbo-sized national sales tax.
The assurance got relatively little attention at the time, drowned out by the many other concessions McCarthy made to win his gavel. But with Democrats already attacking the proposal, some conservatives see it as a political headache in the making.
“This is a political gift to Biden and the Democrats,” Grover Norquist, the dean of D.C. anti-tax activists, said in an interview. “I think that this is the first significant problem created for the Republican Party by the 20 people who thought that there was no downside to the approach they took.”
The idea of a “fair tax” that would replace our current IRS code with a single sales tax was popularized on conservative talk radio in the late 1990s. It has kicked around Washington ever since, popping up in the occasional presidential platform, but never received a vote.
Its current champion in Congress is Georgia Rep. Earl “Buddy” Carter, whose Fair Tax Act would swap out the income, payroll, estate, and corporate levies for a 30% national sales tax. It would also send out “prebate” checks to soften the blow on lower income families, all while abolishing the Internal Revenue Service.
[…]
“Great idea,” Biden deadpanned during a speech Monday. “It would raise taxes on the middle class by taxing thousands of everyday items from groceries to gas, while cutting taxes for the wealthiest Americans.”
It’s true that Donald Trump’s Republican Party is different than Ronald Reagan’s; most notably, it’s even more fanatically committed to upward wealth distribution. But there will always be gullible pundits who will call them “populist” because (points to a 300-tweet thread from Matt Taibbi drooling mad because an anti-vaxx Klan member was denied access to the social media platform of his choice.)