Tom Mulcair's political legacy will be as a strong orator, a champion for the environment and a chief architect of the orange wave that brought the party to historic heights in Quebec.

But he will also be remembered as the man who presided over a failed campaign that dragged the NDP from its first Official Opposition status back to a disappointing third-place finish.

Mulcair faces the end of his leadership after 52 per cent of delegates at the party's convention voted in favour of a leadership contest. His supporters had hoped at least 70 per cent would vote against a review.

Mulcair's biggest accomplishment was also his biggest failing: he managed to steer the party from the ideological left to the mainstream, said Andrea Perrella, a political science professor at Wilfrid Laurier University.

"It alienated those members of the NDP who were attached to a more left-wing alternative to the way Canada is governed," he said. "They weren't looking for Liberal Party 2.0, these members wanted the NDP. And Mulcair took them to the centre."

Return to roots or set sights on power?

Much of the discussion at this weekend's convention revolved around whether the party should return to its social democratic roots, set its sights on power, or find a way to do both.

An internal review concluded the 2015 campaign was "out of sync with Canadians," but many pointed the finger of blame directly at Mulcair.

A look at Tom Muclair’s NDP life and times. From Jack Layton's Quebec lieutenant to Duffy furor to election night loser to now. 3:21

Peter Graefe, a political science professor at McMaster University, said Mulcair faced a much different, and more difficult, political landscape than his predecessor, Jack Layton.

Layton had a likeable personality, but he was also able to shine because he was up against weak Liberal leaders and campaigns.

"The Liberals learned from those things, so it was a much harder landscape for Mulcair to work on," he said.

There have been questions, too, about whether Mulcair tugged the party too far to the right with election platform planks that included a pledge to balance the books each year of an NDP mandate.

Graefe said Mulcair erred in relying too much on others to run the show — an approach that could have stemmed from his political pedigree.

Party-building

"Mulcair did not come up through the NDP — he came through the Quebec Liberal Party, which is a party I suspect where the leading politicians left a lot of the machinery to skilled hands," Graefe said.

"I think he assumed there would be a party beneath what he was doing in Ottawa, and I think he didn't put enough attention and emphasis at ensuring the NDP modernized its approaches to communications, databases; all that party-building kind of work. I think he assumed it was happening and I don't really think it was happening."

Mulcair was first elected to Quebec's National Assembly as a Liberal in 1994. He served in Jean Charest's cabinet for three years beginning in 2003 before quitting cabinet and provincial politics in protest over a condominium development in a provincial park.

That's when he made the leap to federal politics and became Layton's Quebec lieutenant, pulling off a stunning byelection win in the Liberal stronghold of Outremont.

Mulcair became the key architect of the so-called "orange crush" in Quebec in 2011 and sent 59 NDP MPs to Ottawa, choking off the sovereigntist hold the Bloc Québécois had on Quebec for nearly two decades.

The late Jack Layton brought the NDP to Official Opposition status for the first time in history in the 2011 election. (Andrew Vaughan/Canadian Press)

After winning the NDP's leadership after Layton's death, Mulcair was praised for his oratory skills in the House of Commons, grilling then-prime minister Stephen Harper.

'Chief prosecutor' in the House

But while he was earning accolades in Ottawa for being the "chief prosecutor" in question period, he may have been losing touch with the grassroots base.

Instead of presenting a strong visionary platform, Graefe said the NDP strode into campaign thinking if they brought back all the past voters and added some more, that would be enough to get them within striking range.

Now, to regain ground the party must adapt by embracing new technologies, using forms of persuasion and gaining a deeper understanding of the electorate to attract swing voters.

Running a leadership race will be costly not only in terms of finances, but in the way it will take focus away from rebuilding and modernizing the party's institutional structure, Graefe said. But there are also advantages in that it can revitalize the party and bring in new people.

"Trudeau may have had his best day in some ways, so there's a way you can see improved fortunes for the NDP but it will take fresh thinking," he said.

Divisive leadership races

But Cristine de Clercy, a political science professor at Western University, said replacing leaders can be a stressful and divisive process as parties necessarily divide into "camps."

"As we see now in the United States' case of the Republican presidential leadership selection, further divisions such as between party elites and the membership can become large, and controversial," she said. "The key to positioning any party after a leadership contest concerns unity: parties that can unify quickly normally will do better in a general election than those that can not. So this is the key question: will the modern NDP be able to come together quickly enough to mount a successful campaign in the next general election?"