MINNEAPOLIS, Minnesota (CNN) -- A three-judge panel ruled Monday against Republican Norm Coleman in his dispute with Democrat Al Franken over who should be declared the winner of the U.S. Senate race in Minnesota.

GOP Sen. Norm Coleman, left, and Democrat Al Franken are in a battle for a Minnesota Senate seat.

The judges determined that "Franken is entitled to receive the certificate of election" after defeating Coleman by 312 votes.

The Minnesota secretary of state is unlikely to issue that certificate, however, until all legal proceedings have been completed. Coleman has 10 days to appeal the 68-page ruling to the state Supreme Court and could opt to continue into the federal arena if he loses at the state level.

Defense attorney Ben Ginsberg told CNN that the court's order "wrongly disenfranchised" thousands of voters.

"The court's ruling tonight is consistent with how they've ruled throughout this case but inconsistent with the Minnesota tradition of enfranchising voters," he said. "This order ignores the reality of what happened in the counties and cities on Election Day in terms of counting the votes.

"By its own terms, the court has included votes it has found to be 'illegal' in the contest to remain included in the final counts from Election Day, and equal protection and due process concerns have been ignored. For these reasons, we must appeal to the Minnesota Supreme Court so that no voter is left behind."

Franken, saying he was confident he would eventually be certified, urged Coleman not to appeal and to "let me get to work as soon as possible."

"The campaign for this Senate seat has been long and expensive," he told reporters outside his home. "The fight ahead, the fight to rebuild our economy and broken healthcare system and to restore our standing in the world, that's a fight we must win. It's a fight we must win by setting aside partisan gamesmanship and working together."

Coleman, the freshman senator who's seeking a second term, led Franken after Election Day by 215 votes out of nearly 3 million cast in the contest.

That tiny margin triggered an automatic recount, which took nearly two months to complete.

Franken, the progressive radio talk show host, comedian, and former cast member of "Saturday Night Live," led by 225 votes after the statewide recount results were announced at the beginning of this year.

Coleman contested the results and took the case to court. The key issue in the proceedings was whether some rejected absentee ballots should have been included in the recount.

Earlier in the process, the panel allowed the addition of more than 300 wrongly excluded absentee ballots, resulting in 198 more votes for Franken and 111 more for Coleman. But Monday's decision dismisses Coleman's complaint and orders him to pay attorneys' fees.

The court rejected Coleman's arguments that Minnesota's election laws violate the equal protection clause of the U.S. Constitution, acknowledging that some errors were made but that the simple fact of an error does not automatically rise to the level of a violation.

"Equal protection does not guarantee a perfect election," the judges wrote.

Further, the judges said, equal protection does not require that each county in the state handle ballots "with rigid sameness."

The bottom line, the judges said, was that Coleman failed to meet the burden of proof and especially, they said, did not show that "errors or irregularities affected the outcome of the election."

"The overwhelming weight of the evidence indicates that the November 4, 2008, election was conducted fairly, impartially and accurately," the judges wrote in an addendum to the ruling.

"After seven weeks of trial, the factual record is devoid of any allegations of fraud, tampering, or security breaches on Election Day, during the recount process, or during the election contest," they wrote. "On the contrary, the general election resulted in a 'fair expression' of the voters of Minnesota.

If Franken is ultimately determined to be the winner, he would become the 59th member of the Democrats' coalition in a chamber that requires 60 votes to break a filibuster.

All About U.S. Senate • Minnesota • Norm Coleman • Al Franken