The NDP leader said Wednesday he won't be deterred by the fact that Premier Philippe Couillard believes abolishing the Senate is not in Quebec's interests.
But Liberal Leader Justin Trudeau countered that Mulcair is pandering to popular disdain for the Senate in the wake of the expenses scandal, knowing full well that he'll never be able to deliver.
And it's not just Quebec that stands in the way. The country's largest province, Ontario, is also opposed to abolition, Premier Kathleen Wynne's office reiterated Wednesday.
Nevertheless, Mulcair insisted: "In October, the NDP will be seeking a clear mandate from the Canadian voting public. We want a mandate to be able to continue the conversation (with provinces) with a view to Senate abolition."
"Of course the old-time parties, the Liberals and the Conservatives, who see this as an unlimited trough from which they can withdraw public money, from which they can get workers for their election campaigns, they're going to try to fight to keep the Senate," he added following a caucus meeting.
"The Canadians that I meet from coast to coast to coast want to get rid of the Senate."
But Couillard was unequivocal: "Quebec is opposed to the abolition of the Senate and it always will be."
The Senate was created as a regional counterbalance to representation by population in the House of Commons — a feature that protects Quebec as its share of the population has declined, he told a news conference in Quebec City on Wednesday.
"Whether it's dysfunctional these days, I think everyone will agree. But I repeat that it would be contrary to the political interest of Quebec to abolish it. We will oppose this proposal."
Wynne's office said Ontario believes "the Senate plays a valuable role as chamber of sober second thought" and any discussion of reforming it must be about "more than the behaviour of certain individuals" and consistent with the constitutional requirement of provincial approval.
Mulcair acknowledged there are "nuances in every province ... historical things that we're going to try to take into account." But he insisted he's not discouraged by Couillard's position, nor is he about to give up trying to abolish the Senate.
"I'm going to work non-stop. I'm not going to be like (Prime Minister) Stephen Harper and throw in the towel on Senate abolition ... I don't shy away from hard work."
Harper washed his hands of the Senate last year after the Supreme Court of Canada advised that abolishing the Senate would require a constitutional amendment approved by Parliament and all 10 provinces. It also advised that Harper's proposal to impose term limits and create a non-binding election process for senators would require an amendment supported by at least seven provinces with 50 per cent of the country's population.
Trudeau said Mulcair is making a promise he knows he can't keep — just as Harper did with his reform proposals.
"Mr. Harper has promised for years that he was going to change the Senate, with no ability to keep his promises and now we have Mr. Mulcair doing exactly the same thing as Mr. Harper, which is promise what people want to hear but know full well that he's not going to be able to deliver it," Trudeau said.
"That is not responsible leadership."
Trudeau has proposed what he said will result in "real change" to the Senate, without plunging the country back into the constitutional quagmire.
As a first step toward returning the Senate to its intended role as an independent chamber of sober second thought, he kicked senators out of the Liberal caucus last year. If elected, he is promising to create a blue-chip advisory panel to recommend non-partisan nominees for Senate appointments in the future.
Canadians don't want federal and provincial leaders "haggling over the Constitution"; they want them talking about jobs and the economy, Trudeau added.
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