Longtime Conservative MP Marilyn Gladu officially crossed the floor to join the Liberal Party on Wednesday. The defection strikes at the heart of the Canadian opposition. It comes as Prime Minister Mark Carney navigates crippling economic uncertainty fueled by unjustified American tariffs. Gladu cited these exact external pressures as the catalyst for her departure.
The move brings the Liberal caucus to 171 seats. They are now exactly one seat short of the 172 required for a functional majority in the House of Commons. Major Canadian outlets verified the development.
Gladu represents the riding of Sarnia—Lambton—Bkejwanong. She issued a letter to her constituents outlining the decision. Canadians want “serious leadership and a real plan to build a stronger and more independent Canadian economy,” she wrote. She plans to take a more “constructive, collaborative approach” on the government benches.
Prime Minister Mark Carney publicly welcomed her. He praised her “tremendous experience” as an engineer. He highlighted her pragmatic track record in Parliament. The geopolitical stakes are massive. This development reshapes the political landscape across the world as allied nations watch Canada’s internal stability.
Gladu explicitly pointed to the ongoing economic crisis. She told reporters in Ottawa that Canada needs a serious leader to handle the “uncertainty that has arrived due to the unjustified American tariffs.” She framed Carney as the global leader required to build a “resilient” and “self-reliant Canada” during this moment.
The specifics of her departure were confirmed by public statements from both the MP and the Prime Minister.
Statement from Marilyn Gladu re. Her floor crossing. pic.twitter.com/86lHdAHSxT
— Joan Abernethy (@JoansVox) April 8, 2026
How the Defection Rewrites the Balance of Power in the 45th Parliament
Gladu is the fourth Conservative MP to cross the floor to the Liberals since the spring 2025 election. She joins Chris d’Entremont, Michael Ma, and Matt Jeneroux. She is the fifth opposition MP overall to make the jump.
The move represents a stark personal reversal. Just months ago in January 2026, Gladu publicly supported a House of Commons petition demanding that floor-crossing MPs be forced to vacate their seats and trigger a byelection.
Conservative Leader Pierre Poilievre has not yet issued a public response. He secured an 87% approval rating at a recent party convention. But this ongoing exodus of MPs raises structural questions about caucus unity.
The balance of power in the 45th Canadian Parliament is now on the verge of a definitive shift. The Liberals hold 171 seats. Three federal byelections are scheduled for Monday, April 13 in University-Rosedale, Scarborough Southwest, and Terrebonne.
The outcome of those races will directly determine if Carney can secure the 173 or 174 seats needed to pass legislation entirely independently. He would no longer need to rely on the Speaker or opposition support.