After facing allegations of being a socialist, a slew of negative advertisements and a lawsuit challenging her eligibility to serve, Lindsey Williams won a narrow victory in the state Senate 38th District on Tuesday night.

That might have been the easy part. Williams could face what a top Senate Democrat calls a "nuclear option:" a refusal by Senate Republicans, who control the chamber, to seat her.

Senate Republicans have not said that they will actually allow Williams to take office when a new Senate is sworn in early next year.

“No decisions have been made on seating her,” said Jennifer Kocher, a spokesman for Republican Majority Leader Jake Corman. “But there are some pretty clear concerns about her eligibility to serve, given the criteria in the law.”

At issue are questions about Williams’ residency, which were the subject of a Republican-backed lawsuit filed in October. State law requires Senators to have lived in the state for the four years prior to their election. Williams was in the process of moving to Pittsburgh for a job with a teachers union in November 2014. But she voted in Maryland during that year’s general election, and registered as a voter in Pennsylvania in December.

“I believe I have met all the requirements to run for office,” Williams said Friday. “And I wouldn’t have run if I didn’t.”

Williams’ attorney, Chuck Pascal, filed an objection to the lawsuit, saying it had been filed months after a deadline established under state election law. Commonwealth Court Judge Michael Wojcik agreed, and the suit was tossed out.

Pascal’s objections never addressed the substance of the accusations. That’s not unusual for a preliminary objection, which challenges the very right to file a suit before addressing its merits. But Republicans have seized on the fact that Williams didn’t provide evidence of her residency.

Drew Crompton, the legal counsel for President Pro Tempore Joe Scarnati, said in a statement that “Senator Scarnati remains concerned that Ms. Williams has not produced any written information substantiating that she meets the residency requirements under the Pennsylvania Constitution.”

To date, the Republican Senate's criticism of Williams has been somewhat muted.

Through a Republican campaign committee, Scarnati issued an Oct. 25 statement saying the Senate faced “the unsavory and unfortunate prospect of voters electing a state senator who cannot legally serve … The Senate has a responsibility to fulfill its obligation to make sure every member serves in compliance with all the aspects of the Pa. Constitution.”

That statement was not widely circulated during the election, however. Monroeville Senator Jay Costa, who leads the Democratic caucus in the chamber, said he had not had any discussions with Republicans about it since.

“If they go down that path, it is uncharted territory and it would be very harmful to the relationships that exist between the caucuses in the Senate. It would be the nuclear option," Costa added. "But we will be prepared. I’ve already instructed our legal team to address what needs to be prepared.”

Costa outlined what a decision to not seat Williams could look like. On the first day of the next Senate session – which will be New Year’s Day, 2019 – the secretary of the Department of State reads out the results of each Senate election.

“If they make an attempt not to seat her, they would read everyone else’s results, but not hers," Costa said. Williams' status could then be reviewed, perhaps by the Rules Committee, where Costa sits as minority chair.

Costa said it would be up to Williams to prove her eligibility, but he said, “I believe there’s sufficient evidence that she is eligible.”

Williams has furnished copies of a job acceptance letter from the Pittsburgh Federation of Teachers dated shortly before the 2014 election, as well as social media posts that show her in Pittsburgh prior to that date. She said that in 2014, she voted in Maryland early "becuase it was too late to change my registration."

Costa said such a record shows “evidence that she intends to move, and intent is a big part” of determining a candidate's residency.

If Republicans refuse to seat Williams, Costa said Democrats would likely take the matter to court. Duquesne University law professor Bruce Ledewitz previously told 90.5 WESA that the matter would likely end up before the state Supreme Court, which he expected would likely conduct its own review.

"You can't give one party the power to expel members of the other party," he said.

If things get that far, Williams’ case could join several other high-profile election disputes ranging from Florida to Arizona.

Costa said the temperature in Harrisburg is already high, with another bitterly disputed State Senate race in the eastern part of the state. He said Republicans were also upset by bruising TV ads in which Democrats blasted Senate Republicans for stopping legislation to grant sex-abuse victims broader ability to sue the Catholic Church.

“They aren’t happy with us,” he said.

Still, Costa said that an effort to remove the candidate who won the most votes -- even after the residency question had beeen reported by local media and become a campaign talking point -- wouldn't improve matters.

”You can’t convince me that this is the way to go,” he said.