OTTAWA—New Democratic Leader Tom Mulcair may have difficulty staying out of the numbers game. He is doing his best to avoid the trap, saying he will work to secure the support of all party members.

But Mulcair may not have a choice, with NDP Party President Rebecca Blaikie tossing around a challenge even more onerous than the one that sunk former Conservative leader, ousted prime minister Joe Clark.

When the party president cites a number, the die is cast. No one can blame Mulcair for staying away from the numbers game. Many before him have suffered from that fatal mistake.

But it also begs the question on the silent killer of sitting New Democrats in the last election. Why does it take 70 per cent of a party to affirm a leader and only fifty per cent to break up a country?

Mulcair’s orchestration of the Sherbrooke Declaration and the killing of the Clarity Act was a deadly electoral mistake in most of the country, except Quebec. It was the one error he did not even mention in recent interviews providing an autopsy of his own mistakes.

Mulcair’s biggest challenge will be to re-establish socialist credentials. The voting public may prefer the moderate middle. But the New Democratic Party base tilts definitely leftward.

Party insiders are not very happy about an election where their leader deliberately positioned the platform to the right of Liberal leader Justin Trudeau.

Mulcair acknowledges that mistake, saying it was his decision to play it safe, an electoral choice that turned out to be fatal.

He also says he has cleaned house. Some of his longest-serving allies have headed West to work for Premier Rachel Notley. That is hardly a demotion, but a recognition that those who have tasted the potential sweetness of power actually want to work in government.

Languishing for four more years in a rebuilding mode on the federal scene is certainly not as attractive as actually delivering policy today.

Mulcair has his own nemesis out in Alberta with former rival Brian Topp running the operation for Premier Notley and recruiting the castoffs from the good ship Mulcair.

They have a good three years to hone their governing skills in Alberta with the hope of coming back to be part of a winning national team in the next election.

Meanwhile, if Mulcair really wants to dig deep, he has to acknowledge a couple of flaws in his own post-election post mortem.

The leader put a tremendous amount of emphasis on his principled stand in favour of the niqab, pointing to insider polling that saw his party drop 20 points overnight. For sure the decision hurt, but the winning party also had the same position.

So reading too much into that call is not borne out by overall election results. Mulcair’s statements on the niqab were more pointed than those of Justin Trudeau. But his speaking style in general was more aggressive.

Trudeau ran a very positive campaign, while Mulcair admitted his lawyerly rational approach was not appreciated.

It goes deeper than that. And that is why the referendum question cannot be overlooked when New Democrats reflect on their choice for future leader. Mulcair was the architect of the Sherbrooke Declaration, which became his way of demonstrating to nationalist Quebecers that he was one of them. That is probably why they were so shocked to witness his support for multiculturalism by way of the niqab. They knew the Liberals were strong supporters of multiculturalism, so the Grit head-covering stance was expected.

But not so for Mulcair, who was supposed to be “one of them.” Nowhere was the nationalist streak more visible than when Mulcair attacked Trudeau’s father for his position on the War Measures Act.

The timing couldn’t have been worse, as it was the anniversary of Pierre Trudeau’s death, and Justin hit him right between the eyes on that, and on the number that Trudeau considered definitive for referendum purposes. Nine Supreme Court judges validated the Clarity Act and contradicted Mulcair.

Most anglophone Canadians who could remember supported Trudeau’s 1970 actions. By attacking him and by vowing to repeal the Clarity Act, Mulcair lost seats in Atlantic Canada and Ontario that otherwise might have survived the purge.

By refusing to reflect on the problem that he created with the Sherbrooke Declaration, Mulcair ignores a big factor in his defeat.

If it takes more than two-thirds of a party to affirm a leader, how can you not ask the same for a country?

Sheila Copps is a former Jean Chrétien-era cabinet minister and a former deputy prime minister. Follow her on Twitter at @Sheila_Copps.