The word "frontrunner" will not escape Thomas Mulcair's lips — but he is using words like "momentum" when he describes his campaign for the NDP leadership, while pointing to a stack of endorsements.

"I'm never going to use that word," he says of the frontrunner label. "I see that there are spinners employed almost full-time by other camps to use that word," the Montreal MP said during a recent interview in his Parliament Hill office. "I do know that all the information that we're getting is that we're running a good campaign that's being very well-received by the membership."

Mulcair, 57, launched his bid to succeed Jack Layton, who died of cancer this summer, in mid-October and he hopes his five-month campaign peaks with a victory on March 24 at the NDP's convention in Toronto.

The former Liberal provincial politician from Quebec has been called aggressive and impatient but Mulcair shrugs off questions about the impression some might have of him.

"My best answer to any of those questions is the fact that I have more MPs, the people who actually work with me, supporting my candidacy, than all other eight candidates combined," he said. Mulcair now has seven rivals after Nova Scotia MP Robert Chisholm announced Wednesday he is out of the race.

Mulcair has long list of endorsements

Most of the 33 MPs who were named at Mulcair's campaign launch are from the 59-member Quebec contingent of the caucus and Mulcair needs their help to sell party memberships to boost his chances of winning. The NDP has no provincial wing in the province, a "structural disadvantage," Mulcair says he is working hard to overcome.

Quebec is Mulcair's home turf, where he and nine siblings were raised by a French-Canadian mother and an Irish father.

He began his professional life as a lawyer and there are a number of jobs on his resume that Mulcair says have given him experience in public policy, management and leadership.

The political chapter of his career began in 1994 when he was elected to the National Assembly. When the Liberals won government in 2003, Premier Jean Charest named Mulcair environment minister.

Mulcair quit cabinet in 2006 after refusing to sign over provincial park land to developers. He didn’t run in the next provincial election and instead accepted Jack Layton’s invitation to join the federal NDP.

He won the Liberal stronghold of Outremont in a 2007 byelection, winning the NDP's only seat in the province at the time.

Mulcair says experience, elected and otherwise, is the best quality he brings to the leadership race and he also says he has the kind of thick skin that’s needed in politics.

"Quebec City is a tough neighbourhood to learn your politics in, it's very rough and tumble politics so that's prepared me well for the work that I've done after," he said.

'Fought hard' to keep Quebec in Canada

Mulcair says he's used to rolling with the punches but that he was particularly struck by some editorials after he announced his candidacy that he says took shots at him for his defence of the French language and suggested he was a closet sovereigntist.

"For somebody who has spent 30 years fighting to keep Canada together, which is my case, that's galling," Mulcair said.

He didn't watch the sovereignty debates in the 1980s and 1990s on his couch with a remote control, Mulcair says, he "fought hard and passionately to keep Quebec in Canada, but to find a better place" for it within Canada.

The Bloc Quebecois was wiped off the map in May, but no one should be fooled into thinking the sovereignty movement is dead, according to Mulcair.

"No, that's the biggest mistake you can make in Canadian politics," according to Mulcair. People thought it was a thing of the past following the 1980 referendum but then in 1995 the country almost broke apart, Mulcair said.

The NDP set its sights on Quebec and the strategy used there, which clearly paid off, needs to be broadened in order for the NDP to claim victory in the next election, Mulcair said.

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NDP MP Thomas Mulcair says he worked shoulder to shoulder with Jack Layton, who died in August, to build the party's electoral success in Quebec and the work paid off in May when the province elected 59 NDP MPs, including Mulcair. (Sean Kilpatrick/Canadian Press)

Moving from the opposition to government benches will involve reaching out more to cultural communities, First Nations, and young voters, says Mulcair, and it will mean convincing Canadians that the NDP can manage the economy. Helpful in that effort would be securing some high-profile recruits from the financial and other sectors, Mulcair said.

If he were elected prime minister Mulcair said one of the first policy moves he would make would be a plan to reduce greenhouse gas emissions that would include a cap-and-trade system.

Mulcair says he is known as an environmentalist in Quebec and that the legislation he introduced there as a minister was the most forward-looking in North America at the time and probably still is to this day.

Mulcair said he would also resurrect a long gun registry, one that corrects the flaws he says exist in the current system that is being dismantled by the Conservatives.

"For the purposes of public protection you would need a form of registration of firearms, yes," he said.

Mulcair, whose son is a police officer, said he would make registration violations hybrid offences so that police could choose between charging someone with an indictable or a less serious summary offence depending on the circumstances.

First things first though, Mulcair needs to win the leadership before he'll get a shot at taking on Prime Minister Stephen Harper in the next election and governing the country if the NDP wins.

"We’re going to work our butts off to sell memberships," says Mulcair, who describes himself as hard-working, loyal and "very determined."

What he loves about politics is turning ideas into concrete action and he says he's running for leader because he wants to take the NDP's ideas "and to make them real."

He says he and Layton dedicated the last five years to building the NDP's support in Quebec and it paid off in May.

"I did it because I believe that the NDP's vision for a fairer society is the best one for the future of Canada," he said.