A federal Conservative MP has joined the Ontario Liberal Party to cast a ballot in its leadership race, throwing his support behind candidate Eric Lombardi. But could he really become a member?

Matt Strauss, the Conservative MP for Kitchener South—Hespeler, announced this Wednesday that he had taken out an Ontario Liberal membership specifically to support Lombardi in the upcoming leadership contest.

“Today, I joined the Ontario Liberal Party in order to vote for Eric Lombardi,” Strauss wrote on X.

Strauss said that the decision is not as a change in his federal political allegiance, but an endorsement of Lombardi and what he said is “actual liberalism.”

“My involvement in politics has always been about advancing actual liberalism: expanding human freedoms. Free speech, free trade, free choice,” Strauss wrote.

The Conservative MP went on to criticize the federal Liberal Party, arguing that particularly under former prime minister Justin Trudeau it had moved away from those principles and toward what Strauss called “leftist control.”

Strauss acknowledged that he and Lombardi do not see eye-to-eye on every policy question, especially on government spending.

But he praised the Ontario Liberal leadership hopeful as “a true liberal,” describing him as open to new ideas, protective of individual freedoms and willing to challenge progressive orthodoxy.

“He is blisteringly intelligent, hardworking, and refreshingly candid,” Strauss wrote.

Strauss also took a shot at one of Lombardi’s leadership rivals, Navdeep Bains, saying Ontario would benefit from having “a proper Liberal option” in the next provincial election rather than what he called “a content-free ex-Trudeau cabinet minister.”

Strauss’s decision, however, immediately raised another question: whether a sitting Conservative MP is eligible to become a member of the Ontario Liberal Party.

A regional vice-president for the Ontario Liberals pointed to the membership eligibility requirements members agree to when signing up, which prohibit someone from simultaneously belonging to another provincial political party.

“Per the membership eligibility that a person agrees to when they sign up, they cannot be a member of another provincial party and a member of the OLP,” the party official said.

The provision does not necessarily bar Strauss simply because he is a federal Conservative MP. Instead, the question would be whether Strauss is also a member of the Progressive Conservative Party of Ontario.

The Ontario Liberal official summed up the unusual situation more pointedly.

“Meaning… either a Conservative MP would rather be an Ontario Liberal over an Ontario PC,” the official said, “or a Conservative MP didn’t read the fine print when he signed up!”

Strauss, a physician who represents the Waterloo-region riding of Kitchener South—Hespeler in Parliament, encouraged others who share his view to join the party and support Lombardi.

His intervention gives Lombardi an unusual endorsement in a leadership race that is already poised to be heated.

It also creates an unusual political dynamic in Waterloo Region: a sitting federal Conservative openly recruiting members for an Ontario Liberal leadership candidate while saying that the province would benefit from a stronger Liberal alternative in the next election.

Then there are questions from those within the conservative movement.

Jenni Byrne, who managed the federal Conservative’s national campaign in 2025, quickly criticized Strauss for his decision.

“We can have disagreements about issues, but the fact is a conservative is a conservative. Not a liberal . I like Matt, I strongly disagree with this,” she wrote on X.

Deputy Conservative leader Melissa Lantsman reposted Byrne’s comments.

More to come…