In January, Marilyn Gladu Said MPs Who Cross the Floor Should Resign. In April, Marilyn Gladu Crossed the Floor.

On January 11, 2026, the Petrolia Lambton Independent published an article under the headline: “Gladu backs call for automatic by-elections for MPs who switch parties.” In it, Sarnia—Lambton—Bkejwanong MP Marilyn Gladu endorsed a petition put forward by fellow Conservative MP Lianne Rood that called for amendments to the Parliament of Canada Act requiring any MP who crosses the floor to resign their seat and trigger a by-election.¹

Gladu’s quote to the paper was unambiguous. “Really, the whole point of being an MP is to represent your constituents. So if they’re voting you in under one platform — for you to switch for whatever reasons, just seems to me to not be representing what you’re supposed to be there to represent. We elected you under this banner, and if you don’t want to be under that banner, then we deserve a chance to have a redo.”

The petition she endorsed stated that “unrestricted floor-crossing can erode voter trust amid rising political corruption and scandals” and that voters “deserve immediate accountability when an MP switches to another party mid-term, potentially altering Parliament’s balance without endorsement.” Gladu said she could also see by-elections triggered when MPs became independents. At the time she endorsed the petition, two Conservative MPs — Nova Scotia’s Chris d’Entremont and Greater Toronto Area’s Michael Ma — had already crossed the floor to join Carney’s Liberals before Christmas 2025.

On April 8, 2026 — three months after backing the petition — Marilyn Gladu crossed the floor to the Liberals. Prime Minister Mark Carney welcomed her at a press conference in Ottawa. She became the fourth Conservative MP to defect to the government since last year’s election, and the fifth overall, following d’Entremont, Ma, Edmonton MP Matt Jeneroux, and former NDP MP Lori Idlout of Nunavut.²

“The past year has been like no other that Canada has ever faced,” Gladu said in her statement to constituents, “and I’ve heard clearly from constituents that you want serious leadership and a real plan to build a stronger and more independent Canadian economy.” She did not address her January endorsement of the by-election petition. She did not resign her seat. She did not offer voters the “redo” she had said they deserve.³

The mandate Gladu is now carrying into the Liberal caucus was earned as a Conservative. In the April 2025 federal election, she won Sarnia—Lambton—Bkejwanong with 40,365 votes — 53.3% of the ballots cast. Her Liberal opponent, George Vandenberg, received 28,553 votes — 37.7%. The gap was 11,812 votes. She defeated a Liberal by more than 15 percentage points to get the seat she now brings to the Liberal government one year later.⁴

Voters in Sarnia—Lambton—Bkejwanong did not vote for a Liberal MP in April 2025. They voted for a Conservative MP who had, at the time, been one of the party’s most outspoken critics of Mark Carney. On March 15, 2025 — weeks before that election — Gladu posted a video on social media calling Carney part of the “disastrous mess” of inflation she blamed on Justin Trudeau’s government. “I don’t see that he is going to bring any change at all,” she said at the time.

Cohen Berg / Unsplash — Gladu won Sarnia—Lambton—Bkejwanong in April 2025 with 40,365 votes — 53.3% of the ballots cast. She defeated the Liberal candidate George Vandenberg by 11,812 votes. One year later, she joined the party she had just defeated.

The parliamentary math is the reason this defection matters beyond the personal hypocrisy. Gladu’s move brings the Liberal caucus to 171 seats. A slim majority in the 343-seat House of Commons requires 172. Three by-elections are scheduled for Monday, April 13: University—Rosedale and Scarborough Southwest in Toronto (both held by former Liberal cabinet ministers Chrystia Freeland and Bill Blair respectively, and both considered safe Liberal holds) and Terrebonne in Quebec (which the Liberals won by one vote in April 2025 before the Supreme Court annulled the result).⁵

If the Liberals hold the two Toronto seats and win Terrebonne, Carney will have a 173-seat majority — with enough cushion to lose one vote through the Speaker’s chair and still command the House. If they lose Terrebonne, Gladu’s defection alone carries them over the line to 172. In either case, the floor-crossings from Conservative MPs have done what the election did not: they have delivered a functional majority to a prime minister whose party fell short at the ballot box.

A prime minister assembling a majority through floor-crossings rather than at the ballot box is not common in modern Canadian history. Floor-crossings happen — Belinda Stronach’s 2005 defection from the Conservatives to Paul Martin’s Liberals is the most famous example — but they have almost never been the mechanism by which a minority government becomes a majority government between elections. Most majorities in Canada are won. Carney’s, if consolidated, would be assembled. The Liberals won the April 2025 election with 167 seats. Four Conservative defections and one NDP defection have closed the gap to 171. One by-election, one more defector, or one more seat on Monday — and Carney becomes a majority prime minister without his party winning a single additional seat at the ballot box since election day.⁶

The Conservatives have publicly criticized the recent floor-crossings but have not formally introduced or supported legislation to prevent them. Gladu’s endorsement of the Rood petition in January was about as close as any Conservative MP came to backing a concrete legal change — and Gladu has now spent that endorsement as the most visible defection of all.⁷

There are two ways to read Gladu’s January comments. One is that she meant them — that she genuinely believed, three months ago, that MPs who switch parties should quit their seats and face voters. If that is the case, the only principled action available to her now is to resign her seat and trigger a by-election in Sarnia—Lambton—Bkejwanong. She knows the riding. She won it by more than 15 points last spring. If her constituents support the move, she will win the by-election and arrive in the Liberal caucus with a fresh mandate and her January principles intact.⁸

The other reading is that her January comments were rhetorical — a way to score points against the Liberals by criticizing the MPs who had already crossed. On that reading, the principle was never the point. The principle was a weapon. And a principle used as a weapon against your opponents stops being a principle the moment you need it to apply to yourself.

On January 11, 2026, Marilyn Gladu publicly endorsed a petition calling for automatic by-elections when MPs cross the floor. The petition said voters “deserve immediate accountability when an MP switches to another party mid-term.” Gladu told the Petrolia Lambton Independent that voters “deserve a chance to have a redo.” Three months later, on April 8, 2026, Gladu crossed the floor to the Liberals. She has not resigned. She has not triggered a by-election. She has not offered her constituents the redo she said they deserve. She won the seat last April with 53.3% of the vote as a Conservative who called Mark Carney a continuation of Justin Trudeau’s “disastrous mess.” She now sits in Carney’s caucus, carrying a Conservative mandate into a Liberal government that will — if the math holds — become the first Canadian majority government in modern history assembled not at the ballot box but through the defections of MPs who were elected under another party’s banner. Three months. That is how long Marilyn Gladu’s principles lasted. By her own standard, she should resign the seat.