NDP delegates have given a thumbs' down to Thomas Mulcair's leadership at the NDP convention in Edmonton.

Fifty-two percent of party members voted for a leadership race to be held within a year.

The timeline was extended to two years following an emergency resolution by United Steelworkers national director Ken Neumann, who was one of Mulcair's strongest supporters.

There will be many questions about why Mulcair fared so poorly at the convention when pundits were suggesting that he might generate around 70 percent support.

I suspect that the root of the issue was ideological: Mulcair simply wasn't seen as a real New Democrat and that's why he wasn't given a second chance, unlike previous party leaders.

Mulcair ran a more centrist campaign in the 2015 election, promising to balance the budget every year.

Liberal Leader Justin Trudeau, on the other the hand, pledged to run deficits to stimulate the economy.

Trudeau was also quicker off the mark than Mulcair to promise marijuana legalization and sharply increased government support for arts and culture.

In the end, the Liberals won a majority government and the NDP only captured 44 seats. Since the election loss, Mulcair has tenaciously fought to keep his job.

Mulcair became NDP leader in 2012 following the death of Jack Layton. He defeated several rivals in the leadership race in part because delegates felt that he was most likely to help the party win the next election.

But there were nagging concerns among some New Democrats that he was never as ideologically committed to progressive politics as other leadership candidates, notably Brian Topp and Peggy Nash.

And when Mulcair stumbled in the 2015 election campaign, going from first in the polls to third, he lost his trump card: that he was the best candidate to lead the NDP to victory.

It didn't help him that a true progressive, U.S. senator Bernie Sanders, is running a strong campaign for the Democratic presidential nomination, securing wildly enthusiastic support from young voters.

Mulcair raised suspicions among NDP purists

Mulcair came to the NDP late in life. He had been a Liberal member of the Quebec National Assembly from 1994 to 2007. He was Quebec's environment minister from 2003 to 2006 under then premier Jean Charest.

In 2007, he became an NDP MP after winning a federal by-election in Outremont. That paved the way for the NDP's dramatic breakthrough in Quebec in the 2011 election under Layton's leadership.

Prior to the 2015 election, a Quebec blogger dug up comments Mulcair had made in the National Assembly in 2001 that sounded supportive of former British prime minister Margaret Thatcher.

Here's a translation of Mulcair's remarks, made in French, praising a politician despised by many New Democrats:

A government must provide services to the population. We were talking about roads, sometimes; one can think of health services, to education, all the things we know. But a government should never presume to replace the private market, it does not work. It did not work in England. Until the time of Thatcher, that's what they tried. The government had its nose in everything. A wind of liberty and liberalism in the markets breathed in England, and, instead of being one of the worst performing countries throughout Europe, it has become one of the best performing countries. This interventionism has failed. A government can help create conditions conducive to job creation, but the best way for a government to create jobs is not to play the man or businesswoman, or to try to replace the businesspeople. The best way for a government to create wealth is to let the private market hatch...

The NDP leader also came under fire last year after Maclean's magazine reported that he had held secret meetings with Conservatives in 2007 over possibly working as a senior adviser to then prime minister Stephen Harper.

This was before he became an NDP candidate.

Harper's former communications director, Dimitri Soudas, told the magazine that Mulcair initially agreed to take the position and would run for the Conservatives. But according to Soudas, Mulcair balked at the salary offer of $180,000.

Mulcair disputed this version and claimed that his support for the Kyoto Protocol on greenhouse-gas-emission reductions caused discussions to break down with the Conservatives.

For some New Democrats, it was troubling that he even considered working for Harper in light of his expressed support for "social-democratic values".

These weren't the only examples where Mulcair rubbed the left the wrong way. When Layton was NDP leader, Mulcair spoke out after another NDP MP and deputy leader, Libby Davies, expressed public support for the boycott-divestment-sanctions movement against Israel.

"No member of our caucus, whatever other title they have, is allowed to invent their own policy," Mulcair said. "We take decisions together, parties formulate policies together, and to say that you’re personally in favour of boycott, divestment and sanctions for the only democracy in the Middle East is, as far as I’m concerned, grossly unacceptable."

The criticism of Davies was clear even though she wasn't identified by name.

While Davies and Mulcair appeared to work together in subsequent years, she supported Topp's leadership bid. And last year, Davies decided not to seek reelection in Vancouver East.

Davies still enjoys widespread support on the left side of the party and strongly advocated for the Leap Manifesto at the NDP convention in Edmonton. It calls for an immediate shift to a nonpolluting economy.

It pointed out that there's "no longer an excuse for building new infrastructure projects that lock us into increased extraction decades into the future". In other words: no new pipelines. The manifesto states that it's possible to generate 100 percent of electricity from renewables within 20 years.

Mulcair, on the other hand, didn't mention the Leap Manifesto in his speech to delegates today. Not long after the vote, Mulcair told the convention that he will remain leader until his successor is chosen in a year or just after a year.