Election officials attempted to make headway on Wednesday in determining the winner of the undecided Minnesota Senate race but it is unlikely the state will be able to certify a victor by Friday, as initially intended.

The effort to sort out the final vote in the incredibly narrow contest between Republican Sen. Norm Coleman and Democratic challenger Al Franken has been bogged down in a host of disputes over the way ballots have been counted. The state’s canvassing board, which oversees and certifies statewide election results, is now two days into a review of challenged ballots, in which the voter’s intent was disputed by one or the other campaign.

These challenges — more than 6,500 initially — were issued by the two campaigns during the recount of Senate votes, which ended Dec. 5, although both sides have since withdrawn the majority of them.

The recount was triggered after a Nov. 4 vote tally showed Coleman ahead by 215 votes out of 2.9 million votes cast -- a margin of .007 percent. Minnesota law requires a hand recount in any election for federal or state office in which the margin is less than one-half of 1 percentage point.

At the repeated pleading of the canvassing board, attorneys for the Franken and Coleman campaigns whittled their pile down to less than 1,500 as of Tuesday.

By the end of Wednesday, the board had gone through the 415 challenges made by the Franken campaign, according to tracking done by the Minneapolis Star Tribune.

Of those challenges, the board awarded 234 votes to Coleman, 64 to Franken and determined that 117 votes did not count due to an inability to determine voter intent or a violation of rules. That represents a 44 percent success rate for Franken challenges on votes that likely would have otherwise gone to Coleman — a robust number given expectations that nearly all the challenges would be turned down. It remains to be seen if the Coleman challenges will enjoy similar results.

The review of challenges has been a tedious process — with the five board members poring over paper ballots and debating stray marks, double votes, and other voting discrepancies, one by one for hours at a time.

Secretary of State Mark Ritchie, who chairs the canvassing board, had pegged Friday as the deadline for reviewing challenges but with approximately 1,000 ballots still to be assessed, it looks increasingly unlikely that goal will be met.

The race will not be settled with the dispatching of these challenged ballots, however. There is still the matter of absentee ballots said to have been wrongly rejected, the handling of which was the subject of a Minnesota Supreme Court hearing Wednesday afternoon. Counsel for both campaigns had a chance to present their arguments over the proper forum and method for reviewing these votes.

The secretary of state’s office has estimated that as many as 1,600 absentee votes have been improperly excluded from the count.

The canvassing board issued a recommendation Dec. 12 that Minnesota’s 87 counties review absentee ballots that were initially rejected as invalid, and submit amended vote tallies that include any ballots found to have been incorrectly turned away.

The Coleman campaign disagreed with that recommendation and petitioned the court to address the matter. Coleman attorneys argue that the rejected ballots should not be included in the recount but rather dealt with by the courts.