Majority in the House of Commons: Is the real magic number actually 173 seats?

House of Commons, Wednesday, April 8, 2020, in Ottawa. THE CANADIAN PRESS/Adrian Wyld

OTTAWA — The results in the Montreal-area riding of Terrebonne in the April 13 byelection will have major implications on moving bills forward in the House of Commons.

The vote is one of three byelections to be held on the same day. The two others are in ridings in the Toronto area where Prime Minister Mark Carney’s Liberals are expected to win.

Those two likely Toronto victories would propel the Liberals to 172 out of 343 seats in the House of Commons, giving the governing party a majority. But 172 is still one seat short of the magic number the Liberals would need for smooth sailing through the rules of procedure in the Commons.

Liberal Tatiana Auguste won the Terrebonne riding on Montreal’s North Shore by a single vote in April 2025 over Bloc Québécois candidate Nathalie Sinclair-Desgagné. But the Supreme Court of Canada invalidated the result last month after a court challenge by the former Bloc MP over irregularities.

If Sinclair-Desgagné emerges victorious in the rematch, that creates a scenario where the government would have 172 seats and the opposition parties would hold 171.

However, one of those Liberals is currently the Speaker of the Commons, who is expected to be an impartial referee of parliamentary debates, only voting on motions and legislation when there is a tie.

According to the “House of Commons Procedure and Practice, 4th edition,” which is frequently cited in Parliament, the Speaker is, in theory, free to vote according to his conscience, just like all other MPs. However, voting with the Liberals could draw him into a partisan debate and risk casting doubt on his impartiality. As such, convention dictates that “the Speaker normally votes to maintain the status quo.”

How, then, would current Speaker Francis Scarpaleggia, a Liberal MP from Montreal, vote in the event of a tie? His office told The Canadian Press that he would follow established practice.

If the government tables a bill and it reaches third reading — the final stage of the legislative process in the House of Commons — “he would vote against (the bill) to maintain the status quo,” said his spokesperson, Olivier Duhaime. And at earlier stages, he would vote “for” to encourage discussion, hoping that the elected officials would eventually reach an agreement.

This means that the Liberals, even if they had an official majority of 172 seats, would need the support of at least one other MP to pass a bill.

The biggest dilemma would arise when the Speaker must vote on confidence matters — those that could cause the government to fall and trigger a general election. Financial issues — the passing of the federal budget being the prime example — are necessarily such matters.

So what would happen if the Speaker were to vote on the budget bill during third reading?

“Here, we’re faced with two conflicting factors: namely, what is the interpretation of the status quo in this case? Is it to vote against and bring down a government, or is it to not make a change to the existing situation?” his office said.

“That would be a case-by-case interpretation the Speaker would have to make. I can’t tell you which way he would lean in this instance.”

In other words, the Liberals may need to have 173 out of the 343 seats in Parliament to move their agenda forward.

For Geneviève Tellier, a professor at the University of Ottawa’s school of political studies, the Liberals could cede the Speaker role, because the government seems willing to do whatever it takes to stay in power and legislate with the cards it has in hand. “And if that means I need one more vote and I’m willing to sacrifice my Speaker to appoint someone from the Opposition, well, why not, let’s do it,” she said.

Nothing prevents Prime Minister Mark Carney from proroguing Parliament. That would force a new election for Speaker. But it is difficult to predict the outcome of the only vote that is secret in the House of Commons.

Ultimately, there are still a few options for the governing party. First, the parties could try to find common ground. Second, the Liberals could recruit a fifth floor-crosser from the opposition benches.

In the case of deadlock, Carney could justify calling a general election.

“It’s very possible that this could happen,” Tellier said.

This report by The Canadian Press was first published March 27, 2026.

Michel Saba, The Canadian Press