Case in Brief

A Case in Brief is a short summary of a written decision of the Court, drafted in plain language. These summaries are prepared by staff of the Supreme Court of Canada. They do not form part of the Court’s reasons for judgment and are not for use in legal proceedings.

Sinclair-Desgagné v. Canada (Chief Electoral Officer)

Case summary

The Supreme Court of Canada explains that a federal election was annulled because an Elections Canada error prevented a voter’s ballot from being counted.

In preparing for the federal election held on April 28, 2025, an Elections Canada employee mistakenly printed the wrong postal code on prepaid return envelopes for several mail-in ballots for the electoral district of Terrebonne, Quebec. The employee discovered the error more than three weeks before election day, but did not report it to his supervisors or try to contact the affected voters. The election for that riding was decided by a margin of one vote.

Shortly after the election, a voter’s mail-in ballot was returned to her undelivered by Canada Post because the return envelope had the wrong postal code. As a result, Elections Canada never received or counted her ballot.

The candidate who lost by one vote applied to the Superior Court to contest the election. Under the Canada Elections Act, a voter or candidate can contest an election if an irregularity affected its result. The Superior Court dismissed the application. It found that the postal code error and Elections Canada’s failure to correct it were human errors without dishonest or malicious intent and therefore were not an irregularity. It also said that, even if there had been an irregularity affecting the result, it would have been unreasonable to annul the election.

The Canada Elections Act provides that a decision at first instance on a contested election may be appealed directly to the Supreme Court of Canada on certain conditions. The candidate therefore appealed to the Supreme Court of Canada.

The Supreme Court allowed the appeal and annulled the election. The judgment was delivered orally by Chief Justice Wagner on the day of the hearing with reasons to follow.

The Elections Canada’s error met the test for annulment.

Writing for a majority of judges, Justice Jamal explained that the three-step legal test from an earlier Supreme Court of Canada’s decision in Opitz v. Wrzesnewskyj, 2012 SCC 55 should be applied in this case. For an election to be annulled, there must first be an irregularity, which can include a serious administrative error. Second, the irregularity must have affected the result of the election by affecting the vote count. Third, the court must decide whether to annul the election.

Justice Jamal said that although the Superior Court applied the right test, it made an error at each of the three steps. First, the postal code error, combined with Elections Canada’s failure to correct it for over three weeks, was a serious administrative error and therefore an irregularity. Second, the irregularity affected the result of the election by improperly preventing an elector from voting.

At the third step, Justice Jamal decided the election should be annulled. The number of affected votes was one, which was the same as the margin of victory. This left doubt about who had won the election. Justice Jamal explained that annulling the election in these circumstances supports public trust in the electoral process by ensuring that a federal election is not decided by a known and correctable official error.