The non-binding motion, put forward by NDP parliamentary reform critic Craig Scott, called on the government to begin negotiations with the provinces on abolition of the unelected upper house.
The Conservatives and the Liberals both voted against the motion, which was defeated by a margin of 186-101.
"Despite being elected on a promise to reform the Senate, Prime Minister Stephen Harper has failed to make any changes to the Senate during his seven years in office," Scott said in a statement after the vote.
"He has broken his promise never to appoint unelected senators – in fact, Mr. Harper has now appointed 58 senators, even more than Brian Mulroney."
NDP Leader Tom Mulcair, who was the first on his feet — clad in a tuxedo, no less — to vote for the motion, said earlier Wednesday that he would "absolutely not" appoint senators to the upper chamber should he become prime minister.
The NDP has long been committed to abolishing the Senate, but doing so would be a lengthy process with no guarantee of success, since it would require a constitutional amendment approved by at least seven — and possibly all — provinces.
Even if an NDP government immediately embarked on negotiations to scrap the Senate, Mulcair might find it difficult to get any legislation through a hostile Senate, where the NDP is unrepresented.
Apparently aware of that possibility, Mulcair has for days dodged questions as to whether he'd appoint senators just to avoid parliamentary gridlock until the long-standing NDP goal of abolition comes to fruition.
However, the Conservatives have used that equivocation to accuse Mulcair of opposing their proposal to turn the Senate into an elected chamber because he wants to appoint senators instead.
Mulcair tried to put a stop to that line of attack Wednesday.
"Absolutely not," he said unequivocally when asked if he'd appoint senators should he become prime minister.
He said an unelected chamber is a "scandal" in a democracy.
Prime Minister Stephen Harper also promised in opposition to never appoint senators who had not been chosen by election in their provinces. Once in office, he initially refused to fill Senate vacancies.
However, faced with a Liberal-dominated Senate and a stalled Senate reform agenda, Harper eventually capitulated. He has appointed dozens of senators so that the Conservatives now hold a healthy majority in the chamber — a flip flop for which Mulcair has repeatedly castigated the prime minister.
Harper's government recently sought the Supreme Court's advice on its proposals to turn the Senate into an elected body and impose term limits on senators. It has also asked the top court to advise whether abolition would require unanimous provincial consent or seven provinces representing 50 per cent of the population.
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