If Stephen Harper insists on moving ahead with Senate reform, he can expect the Quebec government to fight him all the way to the Supreme Court.
Others warn that the Prime Minister's plan to permit elected senators who would serve fixed terms could create a patchwork of provincial rules that might also be struck down by the courts.
In all, the upcoming Senate legislation could mark the beginning of a protracted legal and political fight over who has the power to amend the rules that govern the Senate, and to what extent.
Quebec Intergovernmental Affairs Minister Pierre Moreau told The Globe and Mail Monday that the federal government's plans to introduce legislation in June that would set fixed terms for senators and enable provincial governments to hold elections for senators when a seat becomes available would be unconstitutional without provincial consent. Many provinces, Quebec especially, are concerned that elected senators would usurp provincial governments as the foremost representatives of their citizens.
"If legislation is introduced, one of the things we will do is challenge the bill before the Court of Appeal and eventually the Supreme Court of Canada," he said.
Similar Conservative legislation in the past has been stymied by the opposition parties. But now that the Conservatives enjoy majorities in both Houses of Parliament, they expect to turn legislation into law by the end of the year.
While placing term limits on senators appears to have broad support - that limit could be anywhere between eight and 12 years in the new bill - electing senators is fraught with legal and practical difficulties, according to David E. Smith, a political scientist at University of Saskatchewan who is one of Canada's authorities on the Senate.
Even if the federal government has the authority to permit elected senators, he observed, each province would probably enact its own rules for such elections, if deciding to act at all.
"You're going to end up with an array of provincial rules for the indirect election of a national official," he predicted. "And I think that raises some questions."
That is why earlier versions of the bill should immediately have been referred to the Supreme Court for a review of their constitutionality, said Liberal Interim Leader Bob Rae.
Not all provinces are as adamant in their opposition as Quebec. Newly minted British Columbia Premier Christy Clark echoed the opinion of many that the best way to fix the Senate is to abolish it, but since that is constitutionally almost an impossibility, "then I think it should be elected so at least it's legitimate," she told reporters.
"You may see a day when British Columbia is electing senators, and perhaps senators who are term-limited once they get there," she said.
Ontario Premier Dalton McGuinty also advocates abolishing the Senate. He wasn't available for comment Monday, but a senior government official said Senate reform is not a priority for the Ontario government.
NDP democratic reform critic David Christopherson said that the term-limits legislation was "no big deal," while his party would wait to hear what the provincial governments had to say about electing senators, though abolition was still the party's first choice.
But whatever the provincial concerns, Prof. Smith believes that the Conservative legislation might nonetheless attract broad public support.
"If there's any agreement on the Senate, it's that people are not happy with an appointed Senate," he observed. "People don't like it. It doesn't have a democratic base. This would be a step to meet that objection. And it would be a big step."
With reports from Justine Hunter in Victoria and Karen Howlett in Toronto