Lewis, 50, grew up in Willingboro but left to attend college and start his track-and-field career. He bought his Medford home in 2007, eight days after what would have been the deadline for the four-year standard, but he had purchased condominiums in Mount Laurel in 2005 for himself and his mother.
U.S. Third Circuit Judge Thomas Ambro, who last week authored the 2-1 order in Lewis' favor, said Tuesday that he was "hung up" on the fact that Lewis voted in California elections in 2008 and 2009, a point central to the GOP's challenge.
"You can only be a citizen or a domiciliary of one state," Ambro said. "To vote in California you must be a resident, which in California means you must be there a domiciliary. . . . You cannot be domiciled in New Jersey until you cease being domiciled in California, and that happened well after May of 2009."
Lewis' lawyer, William Tambussi, argued that voting in a state does not conclusively establish residency. Lewis cast absentee California ballots in 2008 and 2009, but he maintained ties to New Jersey, where he performed charity work.
Tambussi also argued that stripping Lewis' name from the ballot would harm voters, as Democrats would have to scramble for another candidate. Let the voters decide whether they believe Lewis is a New Jersey resident, he said.
"If we were arguing this in June or July, we could be certain that the voters would have a meaningful choice," he said. "Now we're 49 days out."
Mark Sheridan, a lawyer representing Burlington County Republicans, said Democrats have time to fill the vacancy. In 2002, U.S. Sen. Frank Lautenberg replaced then-Democratic Sen. Robert Torricelli on the ballot 29 days before the election.
At the hearing, Sheridan asked the panel to uphold the state courts' decision to strike Lewis' name from the ballot, the same ruling that was reached by the lower level of federal court this month.
Lewis, he said, "is asking this court to wade into issues that have already been decided."
Republicans had asked for a rehearing, including a request to have the case heard "en banc," meaning that all 13 federal judges would hear the matter. But it is up to the court to determine how many judges hear a case. A majority of the 13 must approve an "en banc" hearing, and such hearings rarely are granted, said Gregory Harvey, a lawyer and election-law expert in Philadelphia.
Ambro, who was appointed to the court by President Bill Clinton in 1999, granted the rehearing Monday and told the lawyers to prepared for oral arguments on three questions: Can a person be a citizen of two states, how does California law define who may vote in the state, and to what extent can a federal court interpret a state constitution.
Anthony Scirica, an appointee of President Ronald Reagan, dissented in last week's order. Scirica, 71, served as chief judge from 2003 until 2010.
The third judge on the panel was Thomas Vanaskie, who was appointed by President Obama in 2009.
The panel's decision could come at any time. The deadline to print the ballots was Monday, but county clerks in the Eighth District - which includes parts of Burlington, Camden, and Atlantic Counties - will hold off for a few days, lawyers said.
Lewis' name remains on the ballot template for now. He hopes to face Republican Sen. Dawn Marie Addiego.
The panel's decision this week could be appealed, either in an "en banc" hearing of the Third Circuit or to the U.S. Supreme Court, but Harvey said it was unlikely either court would take up the matter.
Contact staff writer Joelle Farrell at email@example.com, 856-779-3237 or @joellefarrell on Twitter.