Prime Minister Justin Trudeau is facing the politics of gender, race, language and region as he prepares to make his second appointment to the Supreme Court of Canada.

Mr. Trudeau has invited applications from bilingual candidates from the West and the North to fill the position being vacated by Chief Justice Beverley McLachlin, who retires in mid-December. Six weeks ago, an independent committee gave the Prime Minister a short list of three to five candidates, though he is free to go outside the list. An announcement could be made this month.

To some legal observers, keeping a gender split in place with at least four women on the nine-member Supreme Court is vital.

Story continues below advertisement

"The first rule should be parity at the Supreme Court," retired Quebec Court of Appeal justice Louise Otis told The Globe and Mail.

Chief Justice McLachlin: The Supreme Court's steady hand

Related: Chief Justice Beverley McLachlin to retire after decades of pushing boundaries

But Jean Teillet, a senior Vancouver lawyer who is Métis, said the need for an Indigenous judge is more pressing. "The important point to me is to have women's perspectives. As long as we actually have women on the court, then that issue is taken care of. We need to put an aboriginal on the court because we have not got that." (Pierre Trudeau, father of the current prime minister, appointed the court's first female judge, Bertha Wilson, in 1982.)

And then there are regional politics.

"I'm very much of the view this is a British Columbia appointment," said Ted Hughes, a former deputy attorney-general in the province.

On top of all that, Mr. Trudeau is insisting candidates be functionally bilingual in Canada's two official languages. Independent Liberal Senator Murray Sinclair has said the requirement may stand in the way of putting the first Indigenous judge on the top court.

Story continues below advertisement

Prime Minister Trudeau has made gender equality a priority. He has implemented a 50/50 gender split in Cabinet, and his government's judicial appointments have been roughly 50/50. He has also stressed reconciliation with Indigenous peoples.

In his initial appointment to the Supreme Court, he sought to break free from regional constraints. Under Canadian law, three judges on the top court must be from Quebec. The choice of the remaining six is guided by convention: Ontario receives three, Atlantic Canada one and the West two – of whom one usually is from B.C. Mr. Trudeau opened that competition for Supreme Court justice to bilingual candidates from the whole country, but relented under all-party pressure and appointed Justice Malcolm Rowe, the first judge from Newfoundland and Labrador on the top court.

The Globe spoke to more than 20 senior members of the legal community in several provinces on the condition of anonymity, so they could speak freely about top legal talent and who is making their way through the process.

Two female judges – Alberta Court of Appeal Justice Sheilah Martin, and Saskatchewan Court of Appeal Justice Georgina Jackson – are widely seen as contenders.

At least one Indigenous candidate – University of Victoria law professor John Borrows – is viewed as a contender. He has been studying French. A second possibility is British Columbia's former Representative for Children and Youth, Mary Ellen Turpel-Lafond. She is bilingual.

And at least one white male is believed to be in the running, if a long shot: Chief Justice Glenn Joyal of the Manitoba Court of Queen's Bench. (He is a long shot as much for having been an appointee of the Stephen Harper government as for being a white male.)

Story continues below advertisement

Justice Martin has caught the government's eye. In its first set of judicial appointments last June, it elevated her to the Alberta Court of Appeal from the Court of Queen's Bench.

A bilingual former law dean at the University of Calgary, she has been at the forefront of women's issues. She helped develop the legal arguments for the Women's Legal Education and Action Fund, a highly successful advocacy group, in more than two dozen test cases. Her thesis for her doctorate in law at the University of Toronto in 1991 was on women's reproduction, bias against women in the legal system and the Charter of Rights and Freedoms.

University of Calgary law professor Kathleen Mahoney, who has known Justice Martin personally for three decades, calls her an exceptional candidate. "I am confident that her rich experience in human rights, equality law, ethics, and Indigenous rights would help guide the Court in difficult and complex cases they will be required to decide in the future," she said in an e-mail to The Globe.

Justice Martin also has a background in Quebec's civil code, having studied it while doing a law degree at McGill University. Born in 1957, she would have 15 years before mandatory retirement.

If Mr. Trudeau chooses Justice Martin, the Supreme Court would have two judges from Alberta. (Supreme Court Justice Russell Brown, though born and raised in B.C., was an Alberta judge before joining the court, and is therefore seen as an Alberta appointment.)

Justice Jackson would be the first Supreme Court judge from Saskatchewan since Emmett Hall, who served from 1962-73.

Story continues below advertisement

The bilingual Justice Jackson has been on the Saskatchewan Court of Appeal for a quarter-century. She was an appointee of Brian Mulroney's government. A former business lawyer, she has been a leader in judicial education in Canada and abroad. She is in her mid-sixties.

Gerald Seniuk, a retired judge from the Saskatchewan Provincial Court, said Justice Jackson epitomizes judicial demeanour, by which he means she pays close attention when others speak. "She's pretty solid in terms of her judgments. I've never heard any criticism of her legal reasoning, her fairness and her respect for the litigants and of the process and society. I think of her as a progressive-minded judge, but maybe not somebody who shakes the boat."

Prof. Borrows is the author of several books and an original thinker on how to weave together Indigenous and Canadian law. He has the deep respect of a wide swath of the legal community across the country. Ms. Turpel-Lafond has been a constitutional adviser to the Assembly of First Nations, a Provincial Court judge in Saskatchewan (from which she has been on leave for more than a decade) and an outspoken advocate for children and youth in B.C. Prof. Borrows, Ms. Turpel-Lafond and Justice Jackson declined to comment on whether they are candidates. Chief Justice Joyal and Justice Martin could not be reached.

Chief Justice Joyal, who was appointed by prime minister Stephen Harper in 2011, has been a judge since 1998. He is a former Crown attorney and defence lawyer who practised at the Winnipeg law firm led by Justice Martin's late husband, Hersh Wolch.

In a speech earlier this year which may not find favour among the pro-Charter Liberal government, Chief Justice Joyal said that "judicial dominance" over legislators has grown under the 1982 rights document.