Liberal Leader Michael Ignatieff is urging the prime minister to extend Michaelle Jean's term as Governor General when her five-year appointment expires in September.
In an unusual break with the non-partisan tradition of all things GG, Ignatieff issued a news release Sunday saying the Queen's Canadian secretary consulted him on a successor at Stephen Harper's request.
Jean has served her country with "distinction and honour" and deserves Canada's thanks, Ignatieff said.
"We just think somebody ought to get up and say: 'Bravo, Michaelle Jean; you've done a great job for Canada and in our view it would be great if you continue,"' Ignatieff told reporters after a Sunday speech.
Within hours on Sunday, the topic of Ignatieff's comments was becoming political fodder - just the sort of thing critics of his public declaration warned would happen.
The Prime Minister's Office issued an official statement saying Jean has done "an exceptional job representing Canada" and that she and Harper "have an excellent working relationship."
The governor general is the Queen's representative in Canada, effectively - albeit largely ceremonially - the head of state.
Appointed by the prime minister - formally by the Queen - her roles include the power to name a new government, a particularly sensitive issue in the current minority Parliament.
"One of the governor general's most important responsibilities is to ensure that Canada always has a prime minister and a government in place that has the confidence of Parliament," says the GG's website.
"In addition, the governor general holds certain reserve powers, which are exercised at his or her own discretion."
Her powers were put to the test in December 2008 when she tossed Harper a lifeline and granted his request to prorogue Parliament while his Conservative minority was about to be toppled by an opposition coalition.
"The governor general is non-partisan and non-political," says the website.
Robert Finch, dominion chairman of the Monarchist League of Canada, said Ignatieff's "peculiar" public endorsement risks politicizing the appointment process and compromising the GG's independence.
"I'm a little bit blown away," Finch said in an interview.
"It's certainly unusual for a leader of an Opposition - or anybody, actually - to go public with their suggestions as to who should be governor general.
"It kind of opens the realm to politics and you don't want politics entering into the nomination process of the governor general."
Finch suggested such a move can start a slippery slope, whereby political parties ultimately line up behind one candidate or another.
Jean was appointed by former Liberal prime minister Paul Martin in 2005. The subject of her replacement has been widely discussed since Harper recently confirmed her term would not be extended.
Several names have been floated as potential successors, including disabled-rights campaigner Rick Hansen; former defence chief John de Chastelain; Inuit leader Mary Simon and Reform party founder Preston Manning.
A Facebook page has even sprung up where tens of thousands are advocating Montreal-born actor William Shatner - Star Trek's Captain Kirk - for the job.
"It's time for Canada to boldly go where no country has gone before," it says.
The traditional five-year terms of Canadian governors general have been extended on several occasions - by as much as two years. Among those who've been kept on were Roland Michener, Jeanne Sauve and Jean's predecessor, Adrienne Clarkson.
Said Ignatieff's release: "Ms. Jean has done a superb job. I am calling on Stephen Harper to reconsider his decision to replace her."
He said Canadians were "deeply moved by her strong and passionate performance" after the devastating earthquake in her Haitian homeland, which reportedly killed more than 200,000 people.
Her role in bringing attention to Haiti and its people's plight has been "significant, profound and needs to be sustained," Ignatieff said.
Jean has also been a powerful advocate for aboriginal and Arctic peoples, and a proud commander-in-chief who has stood alongside Canadian troops in Afghanistan, he added.
"As a francophone woman who overcame great obstacles to get where she is today, and as the first black Canadian appointed as governor general, I can't imagine a better role model for young Canadians, particularly young girls," said Ignatieff.