U.S. Senate Republicans such as Minority Leader Mitch McConnell of Kentucky, Sen. Lindsay Graham of South Carolina and Sen. John Cornyn of Texas have urged Coleman to appeal to other courts if he comes up short with the three-judge panel.
One reason, said Loyola election law professor Rick Hasen in Los Angeles, is to raise equal protection arguments under the Supreme Court's Bush v. Gore opinion to prompt a re-vote.
"The argument is that you need to have the same rules in place across the entire state for dealing with similarly situated ballots," he said. "Otherwise that would violate the 14th Amendment's guarantee of equal protection, and be unconstitutional."
Coleman's lawyers argued during the seven-week trial that some counties rejected absentee ballots that others counted, because counties applied election rules to similar ballots differently. For instance, they said Carver County checked absentee ballots to ensure the voters who witnessed the ballots were registered, while Scott County did not.
On Feb. 13, the three-judge panel refused to consider a dozen of 19 separate categories of rejected ballots, which shrunk Coleman's universe of potential ballots to open and count.
The judges excluded categories such as ballots submitted by voters who weren't registered and ballots that arrived late from persons living overseas.
Ohio State University election law expert Edward Foley said it's possible that Coleman could raise constitutional claims on each of those categories of rejected ballots.
"The overriding concept of equal protection may play out differently with each of these categories of ballots," he said. "In fact, it may be more than 19."
But Foley also said election law equal protection claims are wild cards, because the area of law is extremely uncertain.
One reason for that uncertainty is because the Supreme Court's 5-4 opinion in Bush v. Gore is murky. That ruling, which gave the presidency to George W. Bush in 2000, centered on equal protection and due process claims in Florida.
The court said it limited its opinion to "present circumstances, for the problem of equal protection in election processes generally presents many complexities."
“The Supreme Court has not cited Bush v. Gore since it decided the case. Not once.”Law professor Rick Hasen, Loyola
Rick Hasen of Loyola said some of the best legal minds in the country can't agree if the ruling means anything for subsequent election law disputes, including Norm Coleman's election contest.
"Whether it should be or could be is really an open question," Hasen said. "The Supreme Court has not cited Bush v. Gore since it decided the case. Not once has it been cited by any justice of the Supreme Court in any case."
Hasen said lower courts have also rejected the broad claims that Bush v. Gore means states violate equal protection when there are systemic deviations in how they treat similar ballots.
Coleman's claims that similar ballots were treated differently in Minnesota go beyond county by county.
In closing arguments, Coleman attorney Joe Friedberg told the three judges that they changed the vote-counting rules on Feb. 13 when they ruled some types of ballots illegal that the State Canvassing Board had already counted.
"There were rules on Election Day, and they are desperately different from the rules that you're applying. Because you're looking at the statute, and on Election Day, many counties didn't," said Friedberg.
But election law scholar Dan Lowenstein of UCLA said just because different bodies make different decisions doesn't necessarily create a constitutional problem. "It's inevitable that the State Canvassing Board is going to call some questions differently than the court does, and it's just the way the process works," Lowenstein said.
"I just don't see this as coming within Bush v. Gore," he added. "What you're lacking is one agency -- whether that's the court or the Canvassing Board or somebody else -- who's arbitrarily treating things differently, and saying we're going to count ballots from one county and not count identical ones from another county."
Just what constitutional claims the loser of the contest can argue will depend on what the three-judge panel says about those issues in its opinion. Right now, there's no word on when that ruling might come.