A Conservative member of parliament said he will be crossing the floor to join Prime Minister Mark Carney’s Liberals, putting his government just one seat shy of a majority and delivering another blow to the opposition party.

Michael Ma, an MP from Ontario, announced his decision to join the Liberals in a statement on Thursday night, saying it is “time for unity and decisive action”.

Conservative leader Pierre Poilievre responded by saying that Ma has “let down” those who voted for him to oppose Liberal policies and “will have to answer to them”.

Ma’s defection comes one month after another Conservative MP, Chris d’Entremont, crossed the floor to join the governing Liberal party.

It also comes a few weeks ahead of a scheduled leadership review for Poilievre.

Ma said in his statement that Prime Minister Carney is “offering the steady, practical approach” needed “to deliver on the priorities that I hear every day” from voters.

At the Liberal holiday party in Ottawa on Thursday evening, Carney asked Ma to join him on the stage, touting the “big, broad, and growing Liberal tent”.

“You are going to have a much better time spending Christmas with us,” he said.

In his own statement, Poilievre, who has campaigned heavily on affordability issues, said Ma “chose to endorse the very policies he was elected to oppose. The same policies driving up food prices and making life more expensive for all”.

Ma was first elected to parliament earlier this year to represent the constituency of Markham-Unionville, an area north of Toronto.

He defeated the Liberal candidate with just under 2,000 votes. The constituency has flipped between the Conservatives and Liberals over the years.

In early November, d’Entremont from Nova Scotia defected and joined the Liberals shortly after Prime Minister Carney put forward his first fiscal plan. At the time, he said he crossed the floor because he no longer felt represented by Poilievre.

In return, the Conservative Party accused him of breaking his promises to Canadians and of acting on “personal grievances”.

Another Conservative MP, Matt Jeneroux from Alberta, then announced that he would resign later in November, citing family reasons.

Liberal government house leader Steve MacKinnon suggested to reporters on Friday morning that Conservative MPs are frustrated with their party’s leadership.

“There are lots of Conservatives, I assure you, who do not like Poilievre’s approach,” MacKinnon said. “You have seen two to date. There are others, for sure.”

Some Conservative MPs, on the other hand, have expressed disappointment at Ma’s decision.

“When you join a team, you work as a team,” said Ontario Conservative MP Scott Aitchison in a post on X, adding that Ma had voted with the party in the House of Commons for months and attended the Conservative Christmas party a day before crossing the floor.

Laura Stephenson, a political science professor at the Western University in Ontario, told the BBC that the Liberal Party and Prime Minister Carney are likely gunning for a majority in parliament in order to enact their agenda without fear of a snap election.

“The long game is to actually be able to enact the kind of change that they think is necessary,” Prof Stephenson said.

She added that the willingness of some Conservative MPs to cross also suggests a waning appetite for Poilievre’s politics, though she notes that he still maintains a good amount of support in his caucus.

Poilievre’s combative style of politics has been blamed for the Conservatives’ election loss earlier this year. Party members will vote on whether he should stay on as leader at the Conservative convention in January.

He lost his own Ottawa seat, prompting a Conservative MP from a safe Alberta riding to step down and allow him to run there. Poilievre won that seat in August with more than 80% of the vote.

Polling shows Poilievre remains popular with the majority of Conservatives, though that margin is shrinking. An Angus Reid poll released on Thursday revealed 58% of recent Conservative voters back Poilievre, down from 68% in August.