Republican Rep. Mark Sanford (R-SC) voted for the Republican tax plan, but he says the GOP isn’t telling the truth about what this tax bill is. It isn’t a middle-class tax cut, he said; it’s a corporate one.

“Fundamentally the bill has been mislabeled,” Sanford told Washington Post reporter Erica Werner. “From a truth in advertising standpoint it would have been a lot simpler if we just acknowledged really on this bill, which is it’s fundamentally a corporate tax reduction and restructuring bill, period.”

Sanford went on to say if that Republicans just messaged the tax bill accurately — as a corporate tax cut — then there could be a good-faith debate on its merits:

“You can argue the merits or demerits of doing that and what it will or won’t mean in terms of economic expansion and growth, but fundamentally if you look at the bulk of the bill, about two-thirds of it, it’s tied on the business side,” Sanford said. “So there’s trimming, if you will — extras — that are built around indeed trying to help folks at different income levels, but that’s not what the core of what the bill is.”

Sanford’s comments go against Republican leadership’s line on the tax plan, and instead echo a Democratic talking point.

Top Republicans have been selling their tax bill — which gives corporations and businesses a massive tax cut, in addition to making smaller changes for American individuals — as a middle-class tax cut. It’s a pitch that has gotten a lot of blowback from Democrats, who point out that the tax bill primarily benefits the ultrawealthy and business shareholders. The middle-class tax cut shrinks over time, and in the Senate bill it disappears altogether by 2025.

“Spare us the bank shots; spare us the sarcasm and the satire,” Sen. Sherrod Brown (D-OH), who sits on the tax-writing Finance Committee, told Senate Finance Chair Sen. Orrin Hatch (R-UT) during the tax bill’s markup to make this point:

I think it would be nice just tonight to just acknowledge that this tax cut is really not for the middle class; it’s for the rich. And that whole thing about higher wages, well, it’s a good selling point, but we know companies don’t just give higher wages — they don’t just give away higher wages just because they have more money. Corporations are sitting on a lot of money. They are sitting on a lot of profits now — I don’t see wages going up.

What ensued was a shouting match far beyond the policy specifics of the Republican tax bill.

“I come from the poor people, and I have been here working my whole stinking career for people who don’t have a chance, and I really resent anybody who says I’m just doing this for the rich — give me a break,” Hatch said.

Instead of focusing on the merits of a corporate tax cut, as Sanford suggests — which Republicans say will bring back jobs, boost domestic investment and bring historic economic growth — Hatch instead became defensive about the tax bill’s focus on the middle class.

There’s likely a good reason Republican leaders are reluctant to call this a corporate tax cut: Cutting taxes on corporations is really unpopular with the American public, even among Republican voters.

Sixty percent of registered voters think corporations pay “too little” in taxes, according to a September poll from Morning Consult and Politico, surveying a little under 2,000 Americans. A more recent Morning Consult and Politico survey from October found only 39 percent of Americans think cutting the corporate rate should be part of the tax plan — with 59 percent of Republican voters supporting it. Another poll from Pew Research Center showed that 53 percent of Republicans think corporate tax rates should either be raised or stay the same.

If there is a political cost to this proposal, one thing is clear: Republicans either don’t believe it’s true or they just don’t care — and they’re doing their best to highlight secondary aspects of their tax proposal to make up the difference.