After 12 years leading the Liberal Party of Canada, Prime Minister Justin Trudeau said Monday he is stepping down. His resignation sets off a succession battle that will see some of the party’s most prominent figures vying to replace him.

In Canada’s political system, the leader of the Liberal Party, as the head of the largest party in the House of Commons, is also the Prime Minister; when Mr. Trudeau’s replacement as party leader is chosen, they will also assume that position.

The politician will lead the party into the general election to face the conservatives and their leader Pierre Poilievre, who dominate opinion polls. Elections must be held by October at the latest, but the government, under the leadership of a new prime minister, is expected to fall well before then in a vote in the House of Commons.

Mr. Trudeau said the Liberal Party would choose his successor by a vote of its members, a relatively small portion of the Canadian population. Although no one has yet announced their candidacy for the successor of Mr. Trudeau, here are some possible candidates.

Chrystia Freeland

Chrystia Freeland’s resignation last month, a former deputy prime minister and finance minister, has fueled widespread speculation that she will launch her own campaign to lead the Liberal Party.

Ms. Freeland had a successful career in Canada as a senior editor at The Globe and Mail in Toronto and as an international journalist working as a correspondent and editor for the Financial Times and Reuters. Ms. Freeland, who was born and raised in Alberta, returned to Canada to join Mr. Liberals. Trudeau in 2013. She is married to a reporter for the Culture Desk of The New York Times.

After the Liberals subsequently came to power, she played an important role in solving several major issues for Mr. Trudeau, especially in negotiations on the successor to the North American Free Trade Agreement during the first Trump administration.

On Monday, Mr. Trudeau had kind words for Ms. Freeland, though he declined to share what happened between them. People familiar with the events surrounding her departure said that Mr. Trudeau he tried to fire her over a video call and offered her the position of minister without portfolio, which she refused.

Dominic LeBlanc

Dominic LeBlanc, who became finance minister when Ms. Freeland resigned, is a longtime friend of Mr. Trudeau and has known him since Mr. LeBlanc babysat for Mr. Trudeau and his brothers in Ottawa. Both were pallbearers at their fathers’ funerals. Mr. Trudeau’s father, Pierre Elliott Trudeau, was once prime minister, and Mr. LeBlanc’s father, Romeo LeBlanc, served as press secretary to the elder Mr. Trudeau. Later he was the Governor General of Canada, the official head of state as the then representative of Queen Elizabeth.

Mr. LeBlanc was among a Canadian contingent who flew to Florida to meet President-elect Donald J. Trump at Mar-a-Lago, his private club and residence, after he threatened 25 percent tariffs on Canadian goods in response on issues of border security. Mr. LeBlanc was first elected as a member of parliament in 2000, and held various portfolios in the administration of Mr. Trudeau, including most recently as Minister of Public Safety.

Mr. LeBlanc, who is from predominantly French-speaking New Brunswick, considered running for the Liberal leadership in 2012, but changed his mind when Mr. Trudeau told him he intended to do so.

Melanie Joly

Mélanie Joly was Canada’s top diplomat since 2021. Mr. Trudeau encouraged her to take the next step in her political career by accepting a role in foreign affairs despite her own reluctance: Ms. Joly was worried the job might affect her fertility treatments.

Ms. Joly brought her own brand of pragmatic diplomacy to the role, reinforcing the importance of Canada working with leaders who hold opposing views on foreign policy.

“There’s this movement — which I’m deeply against — that if you don’t cooperate with countries, you’re sending a message that you’re strong,” she said. he told The Times. “I think being strong means being able to have tough conversations.”

Ms. Joly led Canada’s Indo-Pacific strategy, but she also faced challenges. She expelled six Indian diplomats from Canada and countered accusations of foreign interference by China and India.

Mark Carney

The team of Mr. Trudeau privately pursued Mark Carney, the former Bank of Canada governor who also ran the Bank of England, to take over from Ms. Freeland as finance minister. Mr Carney and Ms Freeland have been friends for many years, and he is godfather to one of her children.

Those efforts to prosecute Mr. Carney collapsed after Ms. Freeland’s public split with Mr. Trudeau and her resignation from Cabinet. Since then, Canadian news outlets reported, Mr. Carney has been calling Liberal members of parliament seeking their support and advice if he runs for the leadership.

While he was governor of the Bank of England, Mr. Carney has developed a reputation as a speaker who veers into politics, including his views on the financial dangers of climate change. In his recent book, “Values,” Mr. Carney offered a scathing critique of capitalism and argued that markets should serve citizens.