Canada has been down this road before, and it is a bumpy one.

Liberal leadership aspirant Michael Ignatieff wants the Constitution to recognize Quebec as a "nation," in the civic and sociological sense at least. So does the Quebec wing of the federal party, which voted 10 days ago to recognize "the Quebec nation within Canada," and to "officialize this historical and social reality." Delegates to the Liberal leadership convention in early December must now debate this explosive proposal.

There is no mystery to the politics in play. Ignatieff is trying to woo Quebec Liberal delegates, and Quebec Liberals are looking beyond the leadership race to the next election by currying favour with soft nationalists.

But a "winning" strategy for Ignatieff and the Quebec wing of his party could be a losing one for the country. It risks igniting a divisive debate within the Liberal family and a far uglier one across a country still haunted by the Meech Lake and Charlottetown constitutional debacles.

Prime Minister Stephen Harper, alert to the risk, dodged the issue on Friday by saying only that Quebec is an "indispensable" part of a united Canada. Last Thursday, Justin Trudeau attacked the proposal, saying that "nationalism is based on a smallness of thought."

Rather than legitimize folly, the Liberal Party of Canada should put the interest of all Canadians first and reject the Quebec-as-nation resolution as a non-starter. While that will draw howls from some quarters, it is better than courting a full-blown unity crisis by trying to rewrite the Constitution. That would be reckless. Failure would invite catastrophe.

For an intellectual who preaches party unity and national unity, Ignatieff has become a polarizing figure. All the Liberal front-runners accept that Quebecers are a nation, in some sense or other. But Bob Rae and Stéphane Dion, who are Ignatieff's chief rivals, have wisely refrained from raising constitutional expectations they cannot meet. Nothing sets Canadian teeth on edge more than the prospect of another unity crisis. If the Liberals raise Quebecers' hopes and then fail to deliver, as is likely, they will demoralize federalists and energize separatists.

As the Star argued seven weeks ago when Ignatieff outlined his plan for constitutional tinkering, the implications of recognizing Quebec and native groups as "nations" are sweeping, and profoundly risky.

The term "nation" is a loose one, used for United Nations member states, peoples such as the Scots or Welsh, aboriginal communities and many other communities. There are 5,000 self-identified "nations."

But once enshrined in the Constitution, flanked by interpretative clauses, the word would take on heavy legal significance. Nations have the right to self-determination and can secede if they are oppressed. That should cause any Liberal who purports to be a federalist, some uneasiness. Rewriting a nation's political compact is not some academic parlour game.

Some Liberals attempt to wave off such fears, saying recognition would be purely symbolic. That is nonsense. Quebec Liberals want recognition to have interpretative weight. Separatists insist it bring concrete gains.

This debate will not play out in a vacuum. Two generations of Quebecers have been conditioned by separatists to believe that to be normal, a nation must be sovereign. That alone should cause federalist Liberals to reject this folly, before a worse scenario ensues.