Canada's outgoing ambassador to the United States, Frank McKenna, announced on Monday he won't run for the leadership of the Liberal Party, saying he's not ready to commit the next decade of his life to politics.

"Contrary to the belief of some, being prime minister of Canada has not been a burning ambition for me," McKenna told reporters at a news conference in Washington.

"I didn't accept the position as ambassador to Washington to create a platform with such a motive, it was simply an opportunity to provide four more years of service in the interest of my country."

Similarly, McKenna said he did not resign from his diplomatic post to launch into a leadership campaign.

McKenna, who also served as former premier of New Brunswick, said his nearly 16 years in public service were "intensely fulfilling."

"Unfortunately it was also the most completely absorbing experience of my life, I became addicted to my responsibilities seven days a week, 24 hours a day," McKenna said.

"I was unable to find the appropriate balance then, and I am certain I would not be able to find the appropriate balance now."

McKenna fuelled speculation that he would be seeking the party crown when he informed prime minister-designate Stephen Harper of his resignation as Canada's ambassador to the United States last week.

Outgoing Prime Minister Paul Martin, who appointed McKenna to the Washington post just less than a year ago, announced his intention to resign as Liberal Party leader when he conceded defeat to the Conservatives' Stephen Harper.

Though McKenna was touted as the clear frontrunner for the leadership race, he came with some baggage.

Pundits questioned how he would be received in Quebec as McKenna has never mastered the French language.

McKenna was also the first premier to question the wisdom of the Meech Lake Accord to make Quebec a signatory to the Constitution.

Although he later supported the accord, his original opposition sparked questions that eventually helped lead to the deal's failure.

Other candidates

Former deputy prime minister John Manley said last week he wouldn't seek the party's leadership. With McKenna's withdrawal, there is no clear frontrunner.

Brian Tobin, a cabinet minister under former prime minister Jean Chretien,  was reportedly waiting to see what McKenna did, but is said to be still hedging for personal reasons.

Speculation is already turning to other contenders such as former public works minister Scott Brison; recently elected Liberal MP Michael Ignatieff; and former human resources minister Belinda Stronach.

Warren Kinsella, a Chretien loyalist, told CTV.ca the Liberals might need a candidate who can appeal to centre-left voters, rather than compete with Conservative prime minister-designate Stephen Harper for centre-right voters.

He explained why: "What a lot of Liberals are not considering is that (NDP Leader) Jack Layton doesn't want to just increase his base; Jack Layton wants to wipe out the Liberal Party."

Manley and McKenna are from the right wing of the party.

From the left, Kinsella suggested former cabinet ministers Allan Rock (now the Canadian ambassador to the UN), Martin Cauchon and Jane Stewart might make strong candidates.

Those individuals are Chretien loyalists. The party has been riven by a feud between those loyal to Chretien and those to Martin.

Kinsella said former B.C. deputy premier Christy Clark, a Martin loyalist, could be a strong candidate.

However, Kinsella and other observers say it might be good for the party if someone stepped up who wasn't strongly aligned with either camp.

Stephen Clarkson -- a University of Toronto political scientist and author of The Big Red Machine, a book about the Liberal Party -- expressed some disappointment with the quality of the remaining candidates.

"They're not dredging the bottom of the barrel, but they're not particularly strong, given the party's been so powerful in our recent past," he told CTV.

With a report from CTV's Roger Smith