TORONTO — Marilyn Gladu has crossed the floor to join the Liberal Party of Canada, becoming the latest opposition member to enter Prime Minister Mark Carney’s governing caucus.
The move comes just months after Gladu expressed support for requiring MPs who switch parties to seek a renewed mandate from voters through a byelection. In early 2026, she endorsed proposals that would automatically trigger such contests when members change political affiliation.
At the time, Gladu argued constituents should have the final say if their elected representative no longer sits under the party banner they were elected with, saying voters “deserve a chance” to choose again.
In a statement released by the Liberals on Wednesday, the longtime Conservative MP said her decision followed a year of economic uncertainty and feedback from constituents calling for “serious leadership” and a plan to strengthen Canada’s economy.
Gladu, who has represented the southwestern Ontario riding for more than a decade, said joining the government would better position her to advocate for local priorities and contribute to national economic goals, including job creation, trade diversification and housing construction.
Her move marks the third recent floor crossing to the Liberals, following similar decisions by Michael Ma and Matt Jeneroux, both of whom left the Conservative caucus earlier in the current Parliament.
The move brings the Liberal caucus to 171 seats, one short of the 172 required for a majority in the House of Commons.
The shift comes ahead of three upcoming byelections, where the Liberals are widely considered favoured to win, contests that could determine whether the party secures a majority.
Speaking alongside Gladu at a press conference, Carney welcomed her to caucus, calling her a collaborative parliamentarian with significant private-sector and legislative experience.
“Marilyn has tremendous experience in business as an engineer, international business experience, and 10 years, four elections, of experience in Parliament,” Carney said. “One of the most collaborative Members of Parliament, working across party lines on important issues.”
He added that her focus on her riding and willingness to work across party lines would strengthen the government at what he described as a “crucial time” for the country.
Gladu told reporters she was motivated by the government’s focus on economic and national priorities, including trade diversification, housing and public safety.
“These are all the things that Canadians want,” she said. “These are actually the things that the people of Sarnia—Lambton want.”
She pointed to her background as a chemical engineer and global business executive as experience she believes will help advance the government’s agenda.
“I think I have a lot of experience that can help accelerate the government’s priorities,” she said.
Gladu also cited economic pressures tied to U.S. trade actions, saying Canada needs stronger leadership in response.
“We need a serious leader who can address the uncertainty that has arrived due to the unjustified American tariffs,” she said. “We need a global leader with a plan to make a more resilient Canada.”
She added that working within government would be more effective than remaining in opposition.
“I think that will have a better effect inside than it will outside,” she said.
In her initial written statement, Gladu framed the move as a return to her riding’s historical role as a “bellwether” constituency, noting that Sarnia—Lambton had typically elected government MPs for decades prior to her tenure in opposition.
“I have made a choice to do the best thing for our community’s priorities, and importantly, for our country,” she said.
Neither the Conservative Party nor opposition critics immediately responded in the statement release, though floor crossings often draw criticism from opponents who argue voters elected MPs under a different party banner.
Gladu said she intends to continue advocating for local economic development and infrastructure projects while supporting the government’s broader agenda.