Warning of tax increases on millions of middle-class families, Capitol Hill’s top Democrats said Monday that the Republicans’ tax-code overhaul is a political “gift” to the Democrats — but one they don’t want.

“Passing a bill that raises taxes on the middle class, while slashing them for the rich and wealthiest corporations, is political insanity, plain and simple,” Schumer said, speaking at the Democratic National Committee (DNC) headquarters near the Capitol.

“In trying to pass this bill, congressional Republicans are doing their best to put their majorities at risk.”

Pelosi said the Republicans’ bill, by scaling back deductions for many middle-income families while slashing the corporate rate, “has exposed [their] true contempt for the middle class,” particularly those living in the suburbs

“Yes, it’s a gift politically … but that’s not what we’re about. We have to save the country from this unfair tax scam,” Pelosi said.

“What the Republicans are doing is not reform, it’s not even a tax cut. It’s a tax — it’s a tax on middle America.”

The Republicans stand poised to test the merits of the Democrats’ political warnings. House leaders are expected to bring a vote Thursday on their reform package, and members of the Senate Finance Committee began considering a separate version of the bill on Monday .

The two bills share certain features, including a sharp reduction in the corporate rate, a doubling of the standardized deduction and the elimination of numerous special-interest deductions. But they diverge on several major points, like their approach to the state and local tax deduction. The House bill caps the benefit, while the Senate proposal eliminates it altogether.

The Republicans are hoping to reconcile the differences and get the package to President Trump’s desk before Christmas — a remarkably short timeline for legislation of such scope and consequence.

The stakes are high, as the Republicans are scrambling to secure a major legislative victory in a year when they’ve failed to realize most of their election promises, particularly the repeal of ObamaCare.

The Democrats, meanwhile, are fighting just as hard to keep the Republicans’ frustrations mounting by denying them a win on taxes. The Democrats have been energized by a string of victories last week in state and local elections around the country, and they’re hoping to extend that streak into next year.

Schumer characterized the tax bill as a “lose-lose” situation for the Republicans, promising to use the votes as a campaign bludgeon, whether the bill passes or not.

“If they fail to pass it, they lose with their donors and the hard right; if they succeed, the political fallout will be catastrophic,” he said.

“This tax bill will be at the center of our efforts to take back the House and the Senate in 2018,” he added. “Taxes, combined with health care, will be a powerful one-two punch for Democrats on the campaign trail.”

“Sen. Heitcamp talked about how philosophically it’s not what she believes in; she wants to help the middle class. Sen. Manchin [was] very upset by the deficit,” Schumer said.

“I don’t know of a one.”

Pelosi said GOP leaders are asking their members “to walk the plank on a bill that may never become law.”

“They vote for this bill, there’s a political price to pay,” she said. “Not because we’re going to make them pay, but because their constituents are going to make them pay.”