Republicans’ suburban decimation at the polls Tuesday has vulnerable House members increasingly on edge — and it’s likely to make the GOP’s uphill struggle for a big tax bill even harder to achieve.

Democrats shellacked Republicans in elections across the nation on Tuesday, but the GOP’s worst losses by far came in suburbs from Virginia to New York to Washington — the types of places that will be hardest hit by Republicans’ initial tax redistribution proposals.

“The election results are sending a clear signal that middle-class issues like SALT [state and local tax deductions] are going right to the heart of the Trump voter,” Rep. Peter King (R-NY) told TPM.

“To me it’s about the most obvious message you can get. I just hope people listen,” he said, imploring GOP leaders to rethink the contours of the tax bill. “It’s just common sense. These aren’t [just] tough votes, they’re votes that go right against our constituents.”

GOP leaders will need support from Republicans from suburban districts like King’s to pass changes to tax laws through the House — and any members who vote in favor of it are writing Democrats’ attack ads for them.

That puts both suburban Republicans and GOP leaders in a tough spot.

Republicans argue — likely correctly — that if they don’t get tax reform done, their base will be further depressed and (more importantly) deep-pocketed donors will close their wallets, further damaging their chances at holding the House.

“If we don’t pass our tax reform bill, if we don’t get this on the president’s desk, our base is going to be less likely to come out,” Rep. Chris Collins (R-NY), a close ally of President Trump’s, told TPM. “We really need to deliver this. Nancy Pelosi summed it up when she said ‘if Republicans don’t pass this bill we’re going to flip the House.'”

But that doesn’t make it any more palatable for suburban Republicans who’d likely be voting to raise many of their constituents’ taxes — and hurting their own job security.

House Budget Committee Chair Diane Black (R-TN), a key player on tax reform, told TPM not to over-read Tuesday’s results.

“This is one election night, and there are a lot of different factors that effect any election night,” she said, arguing that tax reform is a political must-pass for her conference.

“We’ve promised the American people that we’re going to reform the tax code, and I think we need to reform the tax code,” she continued. “We have got to come through with what we’ve promised people.”

King isn’t the only suburban Republican from a district with a higher cost of living and higher local taxes who is deeply skeptical of the bill — and who thinks the GOP losses should serve as a warning sign a day after college-educated voters abandoned the party in droves and huge turnout from fast-growing minority communities and millennials handed Democrats huge wins from coast to coast.

Many suburban Republicans from higher-tax states have been critical of the House GOP’s tax reform plan, which eliminates a number of provisions like the state and local tax deductions and student loan interest tax deduction that help their constituents in disproportionate numbers.

Those deductions are relied upon by middle- and upper-middle-class suburban voters in states like California, New York, New Jersey, Virginia and Minnesota. Studies show those voters would likely see their taxes go up in future years to pay for the big corporate tax cut Republicans are pushing through.

Republicans facing potentially tough races that have a high number of people reliant on the SALT deductions include Reps. Rodney Frelinghuysen (R-NJ), Leonard Lance (R-NJ), Peter Roskam (R-IL), Lee Zeldin (R-NY), Mimi Walters (R-CA) and Erik Paulsen (R-MN). Near the top of the list: Rep. Barbara Comstock (R-VA), whose district was carried by Virginia Governor-elect Ralph Northam (D) by a double-digit margin on Tuesday.

Democrats warned their GOP brethren of what will befall them if they back the plan.

“If you continue to try and eliminate the state and local deduction you are going to kill suburban legislators who are already in trouble because the suburbs don’t seem to like Donald Trump,” Senate Minority Leader Chuck Schumer (D-NY) said Wednesday. “We say to our Republican friends on this tax bill, as Clinton Eastwood said, You want to pass this tax bill? You want to hurt the suburbs? Make our day.”

According to the Tax Policy Center, a left-leaning think tank, Republicans hold nine of the 20 districts with the most people reliant on SALT deductions, and seven of those who’d be hardest hit by the percentage of their income. That includes a number of swing districts like Comstock’s, which is fourth on that list and where more than half of her constituents claim SALT deductions.

Plenty of other suburban districts with vulnerable members could be hard-hit as well.

Rep. Darrel Issa’s (R-CA), who won a nail-biter of an election last year and is facing another tough challenge, told TPM he wasn’t thrilled with the bill and wasn’t “currently willing to support” it. Nearly half of his constituents claim the SALT deduction, according to a study from the Government Finance Officers Association.

“If we had stuck just to things that generated economic growth and left all the other so-called reforms out we’d have a cleaner bill that’d be easier to pass,” he said. “Once we got into telling people how much we were going to cut their taxes we got into a question of how we’re going to pay for it, and we’re paying for it by raising other people’s taxes, and it happens that it is not evenly distributed by state.”

And King says that’s a good reason that a number of his suburban brethren would be forced to vote against the bill if major changes aren’t made.

“It’s one thing to take a courageous vote if it’s for a good cause. To take a vote that’s going to damage your own constituents makes no sense,” he said. “To me, it’s not tax reform — it’s just a tax increase.”