Will Tom Mulcair continue to be Quebec's man in Ottawa?

Tom Mulcair'sfate as leader of the NDP and his hopes of one day becoming prime minister hinge upon a speech he will give to party members Sunday morning.

Mulcairwill take the podium at 10 a.m. MDT in Edmonton (12:00 p.m. ET). Delegates will then vote on whether to launch a leadership review.

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The process is effectively a vote of confidencein Mulcair. His leadership is safe if enough delegates reject the need for a review.

It is estimated that Mulcair needs to convince at least 70 per cent of delegates to vote against a review. Anything less than that would make it difficult for him to carry on as leader.

Whether he mentions it in his speech on Sundayor not, one of the strongest points on Mulcair's NDP CV is having made the party relevant in Quebec.

MP support

Among Mulcair's largest block of supporters is the party's Quebec caucus, who recentlysigned a letter of support backing Mulcair.

Many of the NDP'sQuebec MPs were first elected in 2011, amid the so-called Orange Wave. Mulcair played a leading role in that campaign as leader Jack Layton'sQuebec lieutenant.

The party won 16 seats 25.4 per cent of the vote in Quebec in the last election. That's down from the 59 seats it won in 2011, but was stillthe party'ssecond-best performance in the province.

Before Mulcair joined the party in 2007, it had only ever held one seat in Quebec.

But Mulcair's experience in Quebec politics he was a cabinet minister in the early years of former premier Jean Charest'sLiberal government has proved to be a double-edged sword.

He is a recognizable figure in the province, and has proved himself sensitive to questions of identity and language, which have allowed the party to make inroads among francophone voters.

His past as a Quebec Liberal, though, has some in the province questioning his progressive bona fides.

"I think he dragged the NDP to the right, to the Liberal side of things," said AlainCharbonneau, ridingpresidentfor the party association inLasalle,Emard, and Verdun.

"The last thing that Canada needs istwo Liberal parties."

Charbonneau, needless to say,will be voting for a leadership review on Sunday.

But if Dippers do decide to show Mulcair the door, it is open question whether the party can find a leader as adept at navigating the waters of Quebec politics.

And even with Mulcair gone, any successor will have to contend his legacy:the 16 Quebec MPs are thelargestprovincial block in the party's 44-seat caucus.

All riding on the speech

For those still undecided, a lot will depend on whatMulcairsays in his speech on Sunday.

"Most people are not on one side or the other in favour or not in favour of a leadership review," saidAllisonTurner, a Montreal lawyer who ranunsuccessfullyfor the NDP in the last election.

"It's quite divided actually. It's going to be really interesting to see what happens on Sunday."