Senate Minority Leader Chuck Schumer (D-N.Y.) asked Senate Majority Leader Mitch McConnell (R-Ky.) to delay the vote on the tax bill until newly elected Senator-elect Doug Jones (D-Ala.) can cast a vote. (Reuters)

Democrats warned Wednesday that Republican plans to speed ahead with revamping the nation’s tax code could spell more electoral trouble for President Trump and his party next year, especially with young people and suburban families.

Just hours after Republicans suffered a humiliating defeat in a special U.S. Senate election in the GOP stronghold of Alabama, party leaders unveiled a compromise on a sweeping $1.5 trillion tax plan that will significantly lower corporate rates and slash taxes for upper-income households.

But Democrats — now able to tout recent electoral victories in deep-blue New Jersey, swing state Virginia and Republican Alabama, all of which showed signs of voter discontent with GOP policies — called on Republicans to wait to vote on their tax plan until Democrat Doug Jones, the winner of the Alabama race, arrives in Washington.

Mired in the minority and sapped of any control of Capitol Hill, Democrats crowed about the implications of the Alabama contest, touting how the party’s base — young people, black women and, increasingly, suburbanites — turned out at higher rates than normal for an off-year election. Jones also cut into Republican advantages in counties that overwhelmingly backed Trump in last year’s presidential election.

If Republicans move ahead with their plans to rush tax reform, “there will be many more Alabamas in 2018,” Senate Minority Leader Charles E. Schumer (D-N.Y.) said. “Many more.”

Senate Minority Leader Charles E. Schumer (D-N.Y.) and House Minority Leader Nancy Pelosi (D-Calif.) speak before the House-Senate conference on taxes Wednesday. (Joshua Roberts/Reuters)

“The suburbs are swinging back to us,” he told reporters, adding that the GOP tax plan is “an anti-suburban tax bill” because it would reduce how much homeowners can deduct in state and local taxes.

Republicans, however, ignored the Democrats and said they did not expect any slowdown in the tax push, citing a Christmas deadline for action that had been set months in advance.

“The people back home want to get it done now,” said Sen. David Perdue (R-Ga.).

In closed-door meetings of Republican lawmakers Wednesday on both sides of Capitol Hill, the Alabama results were not even a topic of official discussion. Sen. John Neely Kennedy (R-La.), leaving a Senate Republican lunch meeting, said the topic simply hadn’t come up.

“Changing the entire 10 million-word tax code is of great magnitude, too, so that’s what we spent our time talking about,” he said.

Democratic leaders Rep. Nancy Pelosi (D-Calif.) and Sen. Charles E. Schumer (D-N.Y.) criticized the GOP tax plan for "robbing the future" on Dec. 13. (The Washington Post)

The House and Senate are poised to vote on the GOP tax plan by the end of next week.

When exactly Jones will join the Senate remains unclear. Alabama’s secretary of state, the state’s senior elections official, said Tuesday that the soonest the election will be certified is Dec. 26 or 27. The Senate’s holiday break is scheduled to begin Dec. 22, and senators are not expected to return until Jan. 3, although that schedule could change.

Calls to slow down the tax plan are only the most immediate consequences of Jones’s unlikely victory. His arrival will cut the Republican majority in the Senate from two votes to one, making it even harder to move the GOP legislative agenda forward without some bipartisan cooperation. Possible efforts to cut back entitlement programs or replace health-care policy with a more conservative alternative, already difficult, could be impossible in a Senate divided 51 to 49.

One veteran Democrat played down the notion that Jones could scramble the Senate’s political dynamic in a significant way, citing his lack of a voting record that would indicate reliable support for the Democratic agenda and the pressure he may face from his conservative state.

“I don’t know what he wants to do, and he’ll have to decide what he wants to do,” Sen. Patrick J. Leahy (D-Vt.), the Senate’s longest serving member, said. But, he added, the mere presence of Jones could shape the way Republicans and the White House craft their priorities for the coming year.

During the campaign, Jones ran as a centrist, and in his victory speech, he spoke of the need for politicians in Washington to find “common ground.”

Schumer conceded that he doesn’t know whether Jones would back the GOP tax plan, saying, “He will make a decision based on what he believes is best for the people of Alabama.”

Sen. Lindsey O. Graham (R-S.C.), who has become friendly with Trump and frequently plays golf with him, said he has spoken to the president in recent weeks about working on bipartisan deals next year and expects more willingness to reach out to Democrats after a year of focusing on GOP concerns.

“In terms of base politics, he’s done a lot — regulatory reform, [confirming Supreme Court Justice Neil M.] Gorsuch, the tax cut. In the bipartisan portfolio, there’s not a whole lot in it,” Graham said. “There needs to be both. He gets it. Infrastructure is a bipartisan project; immigration is bipartisan.”

Sen. Joe Manchin III (D-W.Va.), a key moderate Democrat who stands to see his clout build in a closely divided chamber, also urged Trump and Republicans to seek new ways to work with Democrats.

“Every time I’ve been around the president, I’ve always felt he’s more comfortable working on something bipartisan than on something partisan,” he said in an interview. “The push he’s getting from his party is, it’s all for the base.”

In calling for a delay in the tax debate, Democrats pointed to their party’s decision to slow down controversial health-care legislation in 2010 when a Republican, Scott Brown, won a special election to fill the Senate seat of the late Edward M. Kennedy in liberal Massachusetts.

Democrats cited comments that Sen. Mitch McConnell (R-Ky.), now the majority leader, made in January 2010 in the immediate aftermath of Brown’s win, calling on Democrats to slow down the passage of the Affordable Care Act until he was sworn in.

“I think the message of the moment is that the American people, all across the country, are asking us, even in the most liberal state, Massachusetts, to stop this health-care bill,” he said the day after Brown was elected.

The Massachusetts election was squarely focused on the Democratic health-care bill, however, while the Republican tax bill was only an ancillary issue in an Alabama election that was more squarely focused as a referendum on the character of the Republican candidate, Roy Moore.

Ultimately, Democrats ended up using special procedures to pass the health-care bill without Brown’s vote — the same “reconciliation” rules Republicans are using to pass the tax plan without Democratic support.

Publicly, Democrats cite the need to wait for Jones as a reason to slow debate on tax reform. But they also know that a delay could help build opposition — just as the summerlong fight among Republicans over how to repeal the ACA derailed the effort as closer scrutiny sparked broad public opposition.

Republicans offered their own reasons why Alabama’s Luther Strange, the outgoing Republican placeholder, should vote on the bill rather than Jones.

“He doesn’t know anything about it,” Sen. Bill Cassidy (R-La.) said of Jones. “He’s been on a campaign; he’s not been studying the bill. . . . Ideally, you want somebody who’s more informed than not, and Luther’s informed.”

For moderate Democrats such as Manchin facing reelection in 2018 in states Trump won handily last year, waiting might give them more time to rewrite the tax plan.

“There’s no economic meltdown. The stock market’s doing fine. There are 17 Democrats who are ready to work on a bipartisan tax bill if they slow things down,” Manchin said.

Manchin and at least 16 other members of the Senate Democratic caucus have tried at various points to work with Republicans on tax reform. But they have rebuffed pressure from Trump, McConnell and other Republicans to support the tax plan, given its generous tax cuts for high earners and the repeal of the ACA’s mandate requiring individuals to purchase health insurance.

Earlier this month, the Senate passed the GOP tax plan by a single-vote margin, 51 to 49. Had Jones been seated then, however, Republicans still would have been able to pass the measure, albeit with Vice President Pence casting the tiebreaking vote.

Democrats are hoping that at least two Republican senators will step away from the fast-moving legislation in the coming days, forcing GOP leaders to pull back. But on Wednesday, key GOP senators Susan Collins (Maine), Jeff Flake (Ariz.) and Ron Johnson (Wis.) said they saw no reason for delay.

But one potential complication arose for GOP leaders: The office of Sen. John McCain (R-Ariz.), who has an aggressive brain tumor and missed Senate votes Wednesday, issued a statement explaining that he is being treated at Walter Reed National Military Medical Center in Maryland.

“Senator McCain looks forward to returning to work as soon as possible,” said the statement, which not did say when he might return.

Erica Werner and David Weigel contributed to this report.