The New Jersey state Supreme Court ruled Wednesday that the Democratic Party can replace Sen. Robert Torricelli's name on the November ballot with former Sen. Frank Lautenberg.
The ruling gives hope to Democrats scrambling to retain their one-seat majority in the U.S. Senate through the Nov. 5 election -- but Republicans vowed to appeal the decision to federal court.
The 7-0 decision cited previous rulings that said election law should be broadly interpreted to "allow parties to put their candidates on the ballot, and most importantly, to allow the voters a choice."
The case isn't over yet: In Washington, Alex Vogel, a lawyer for the Republican Senatorial Campaign Committee, said the GOP and Republican nominee Douglas Forrester would ask the U.S. Supreme Court on Thursday morning to stay the New Jersey high court ruling, in effect freezing Lautenberg's name off the ballot.
"The Torricelli-Lautenberg machine's disregard for the rule of law, fair elections and the people ... will once again make our great state the butt of national jokes," Forrester said Wednesday night.
Vogel also said a separate federal suit would be filed in New Jersey on behalf of overseas military personnel who have requested absentee ballots. "Federal law requires they should already have gone out," Vogel said. He added that state Supreme Court's ruling leaves unclear when those ballots would be distributed.
The fight over which Democrat will appear on the Nov. 5 ballot erupted Monday after Torricelli dropped his faltering re-election campaign amid lingering questions about his ethics. He was admonished over the summer by a Senate committee for allegedly taking lavish campaign gifts from a contributor to his 1996 campaign.
Late Tuesday, Democrats settled on the 78-year-old Lautenberg as their substitute candidate.
Republicans say it is too close to Election Day to replace Torricelli and that Democrats shouldn't be allowed to dump a candidate who was trailing in the polls. The GOP also said state law bars replacement candidates less than 51 days before an election; Torricelli withdrew 36 days before Election Day.
"I believe the statute should be enforced as it presently reads," Forrester's lawyer, Peter Sheridan, told the state justices.
But in its seven-page ruling, the court said it was more important to have a ballot "bearing the names of candidates of both major political parties" and that state law didn't rule out the possibility of a vacant candidacy within 51 days of the election.
Under the ruling, the state Democratic Party must pay for ballots to be reprinted, and that military and overseas ballots should get priority. State election officials estimate reprinting will cost about $800,000.
Republican officials said they planned to file a motion in federal court Thursday to block any move that would alter ballots already sent to military personnel and civilians overseas.
The GOP also wants a federal judge to compel the state to immediately mail out any remaining absentee ballots, which have been held up under a state court order.
For nearly three hours Wednesday, the justices -- four Democrats, two Republicans and one independent -- peppered lawyers, state election officials and even some third-party candidates with detailed questions.
Some wondered whether it was possible this late in the game to print and pay for new ballots -- and whether it was fair to bend the rules to accommodate the Democrats' request.
"Here we have a candidate, he's capable, he's able, he's just changed his mind about running," Associate Justice Jaynee LaVecchia said.
Democratic lawyer Angelo J. Genova told the court that Torricelli is no longer the party's choice, and voters should not be forced to check his name and hope a replacement would be selected later.
"I think he has effectively created a vacancy by his withdrawal. He's not a candidate. He's not a candidate for public office," Genova said.
While Democrats waited for the court to act, they planned Lautenberg's campaign and negotiated the transfer of funds and operations from Torricelli's operation. A kickoff party was scheduled for Wednesday evening.
Still, there are concerns that New Jersey's election will be decided in federal court, as Florida's was during the 2000 presidential race.
No one is sure how voters will react if the court ruling is seen as partisan or if the legal fight will divert attention from the campaign, said Ingrid Reed, a professor at the Eagleton Institute of Politics.
"They sure knew about Torricelli and had an informed opinion about him. They were paying attention," Reed said. "I think the voters were listening, and certainly if Democrats are going to get any votes out of this switch, they are going to get the votes from Democrats they may have lost thanks to the scandal."
Fox News' Eric Shawn and Carl Cameron and The Associated Press contributed to this report.