Canada's top court is now weighing a question it has never considered: How fraught with error must an election be before judges decide to overturn it and order a new one?
The Supreme Court announced Tuesday it would reserve judgment after hearing a Toronto MP's appeal of a lower-court decision to toss out the 2011 federal vote results in the riding of Etobicoke Centre.
The court is nevertheless expected to render a ruling quickly, having interrupted its summer break for the first-of-its-kind case.
The integrity of Canada's election system came under intense scrutiny Tuesday as Conservative MP Ted Opitz, who won the riding of Etobicoke Centre by a razor-thin margin, fought to keep his seat during 3 1/2 hours of Supreme Court hearings.
He is challenging an Ontario judge's decision this past May to void his electoral victory after concluding that 79 voters cast ballots without evidence that they were properly cleared to do so. That's more than three times Mr. Opitz's 26-vote margin of victory.
The court must now decide what might do more damage to Canada's electoral system: allowing Mr. Opitz to keep his narrowly won seat despite evidence some voters were not properly registered, or throwing out the 2011 ballot and holding a new election.
Defeated Liberal MP Borys Wrzesnewskyj, who has spearheaded a challenge of the 2011 vote with $300,000 of his own money, wants a new vote.
Supreme Court judges questioned whether Canadians might lose faith in the voting process if Elections Canada paperwork errors were allowed to stand and no by-election held.
Kent Thomson, a lawyer for Mr. Opitz, argued before the Supreme Court Tuesday that mistakes by poll clerks are inevitable and that the absence of records that might show these voters were properly verified in Etobicoke Centre shouldn't invalidate the election.
"It can't be trivial errors" that trigger the overturning of an election, Mr. Thomson said.
But Madame Justice Beverley McLachlin asked whether letting these errors stand might diminish regard for Canada's electoral system.
"The thing that has the potential to undermine the confidence of the public in a particular electoral result narrowly, and the system overall, is the speculation … about what took place," she said in court.
If we "excuse too many errors," she said, "what will that do to the overall Canadian electoral system?"
Gavin Tighe, lawyer for Mr. Wrzesnewskyj, said properly verifying voters' identification is a fundamental safeguard in the political process.
"It's important to know the person who is voting is actually that person," he told the Supreme Court.
Otherwise, Mr. Tighe said, "that vote can't count."
Mr. Thomson, acting for Mr. Opitz, argued what would be worse is telling Canadians that an election can be overturned by Elections Canada clerical errors.
"People will lose respect for the electoral process if they find out they can be disenfranchised by the mistake of a poll clerk in making an entry in a document."
Mr. Thomson warned that if the 2011 results in Etobicoke Centre are thrown out, it could trigger a multitude of court battles in the years ahead as election losers sue for do-overs.
"If it is right that people can pour over thousands of election documents in a forensic anal ysis to spot every error made in the document – and when they spot an error, toss aside a vote, this court will be very busy in contested election applications from here to eternity," he said.
That would leave courts facing legal challenges of election outcomes "from here to doomsday," he said.
But Madame Justice Marie Deschamps said if the election "process is allowed to be conducted in such a lousy or negative manner" then in the long-term the voting system will be more vulnerable to error.