OTTAWA — Leadership hopeful Bob Rae is warning Liberals that there is no appetite in the country for constitutional adventures or "abstract debates" over Quebec's identity.

While he wouldn't go so far as to say the Constitution should never be reopened, Rae made it clear Friday that it wouldn't happen under his watch.

"I've been through this. I've been through Meech. I've been through Charlottetown. I've been through it all," Rae said, recounting his experiences with past failed attempts to enshrine Quebec's distinctiveness in the Constitution.

"There is no appetite in the country for this kind of an adventure. There simply is not that appetite there and the leadership of the country has to recognize that," he added.

"You should not raise expectations that cannot be met and we should not be engaging in an abstract debate in this country at this point in time. We should be focusing our attention on issues that really matter to people."

Rae issued the warning during the launch of his latest book, "Canada in the Balance," a slim paperback that outlines his blueprint for the country.

His admonition came even as he and other leadership contestants continued to search for a compromise to defuse a potentially explosive resolution that could rupture the party during its leadership convention later this month.

The resolution, put forward by the Quebec wing of the party and to be debated at the convention two days before the new leader is chosen, calls on Liberals to recognize Quebec as a nation within Canada. It also calls on the party to create an expert task force to advise the next leader on how best to "officialize" such recognition.

Only front-runner Michael Ignatieff has wholeheartedly supported the resolution. The other seven leadership contenders have conveyed varying degrees of discomfort with it, including fears that the word "officialize" could be interpreted to mean entrenching Quebec's nationhood in the Constitution.

Rae was an ardent supporter of the ill-fated Meech and Charlottetown accords, which would have enshrined recognition of Quebec as a distinct society. As recently as last August, he said he has always supported the idea that Quebec "is a nation, it is a distinct society which we need to recognize in our Constitution."

Ignatieff's supporters have pointed to such musings to accuse Rae of flip-flopping on the issue.

Rae acknowledged Friday that he's never ruled out re-opening the Constitution eventually.

"Never is not a word I've used. I stand by what I've written, what I've said."

Nevertheless, he said political leaders need to learn from past mistakes and respect the will of Canadians, who don't want another round of divisive constitutional wrangling.

"I'm not somebody who is going to set this country on a constitutional adventure, whose consequences and whose outcome I'm not certain of," Rae said.

He added that he believes the country makes the best progress and is most united "when we focus on practical measures" rather than esoteric constitutional nostrums.

Rae won an endorsement Friday from one of his fiercest former foes. Richard Mahoney, who was president of the provincial Liberals in Ontario when Rae was the province's NDP premier, proved that at least some Ontario Grits are prepared to let bygones be bygones.

Indeed, Mahoney said he thinks Rae is "the best person ... to help us win Ontario" in the next election, notwithstanding memories of his recession-ravaged term as premier, when deficits ballooned and taxes soared.

Mahoney, a top adviser to former prime minister Paul Martin, noted that polls show Rae is the first choice of Ontarians and the only contender to poll better than NDP Leader Jack Layton in the province.

Meanwhile, Quebec Intergovernmental Affairs Minister Benoit Pelletier said Canada should recognize in the Constitution that Quebec is a nation.

"To those in the rest of Canada who fear that renewed constitutional debate would specifically deal with Quebec, I saw that it is inevitable," he said in the Quebec legislature.

Regardless, Pelletier said conditions aren't present right now to ensure success in such talks.