The Supreme Court of Canada has wrapped up a first-of-its kind hearing into an overturned election, with the judges reserving their decision.

Defeated Liberal candidate Borys Wrzesnewskyj, who brought the original suit in the lower courts, says the case is vital to maintain confidence in the integrity of the voting system.

The lawyer for Conservative MP Ted Opitz argues that the voting rights of people in the Toronto riding of Etobicoke Centre were trampled by simple record-keeping errors.

His lawyer, Ken Thomson, says the lower-court decision to overturn Opitz's win in last year's federal election disenfranchised all the voters whose ballots were thrown out.

Thomson told the Supreme Court judges it's hard to imagine that such an important constitutional right could ``hang by so fine a thread.''

Opitz won the riding by just 26 votes over Wrzesnewskyj in last year's federal election, but Wrzesnewskyj went to court, claiming procedural irregularities.

Earlier this year, an Ontario Superior Court judge found that Elections Canada officials made clerical errors at the polls.    

After Justice Thomas Lederer threw out 79 votes and overturned the final result, Opitz appealed the case to the Supreme Court, the first time that has happened.

Only five other election results have been nullified by the courts since 1949. None of those rulings were appealed and byelections were quickly called to re-determine the will of the people in each riding.

The outcome of the case will determine whether Prime Minister Stephen Harper has to call a byelection in Etobicoke Centre.  If the lower court ruling is upheld, Harper will have six months to call the byelection, but Wrzesnewskyj said he shouldn't wait that long.

The Etobicoke Centre result was overturned on the grounds that paperwork was not properly filled out for voters who needed someone to vouch for their identity or who were left off the list of electors.

In his ruling, Lederer specifically stressed the irregularities were the result of clerical errors by well-meaning Elections Canada officials, not the product of fraud or intentional wrongdoing.

Since then, however, Wrzesnewskyj has resurrected other more serious allegations of ballot-box stuffing and voter suppression by Opitz's campaign, though nothing has been proven.