As they gathered Tuesday to plot strategy for next week's return of Parliament, NDP MPs maintained they've got their eyes firmly fixed on the real prize -- winning power in four years -- and won't allow the leadership race to divide or distract them.
But there were already signs that may be easier said than done, with tension emerging between the two apparent frontrunners in the leadership race.
Montreal MP Thomas Mulcair took a thinly veiled shot at the speed with which his main rival, party president Brian Topp, launched his leadership campaign.
Topp's name began circulating as a leadership contender one day after Layton died from cancer last month, raising eyebrows among some grief-stricken New Democrats. On Monday, Topp became the first to formally announce his candidacy, with impressive backing from party icon and former leader Ed Broadbent and Quebec MP Francoise Boivin.
Mulcair, who has yet to declare, suggested his slower approach is more respectful to Layton's memory.
"We're taking our time. A lot of people, especially those of us who were closest to him, are still under the shock of the loss of Jack Layton," Mulcair told reporters.
"We also want to respect his memory and go forward in due order."
Mulcair's claim to being among Layton's closest confidants appeared aimed at countering speculation that Layton may have preferred Topp to succeed him. Topp was a key architect of Layton's electoral successes and was among a tiny handful of close aides who helped the former leader craft a death-bed statement to Canadians.
That said, Mulcair left little doubt he'll be a candidate in the race, which will culminate with a leadership vote on March 24.
"What I'm doing right now is meeting with people from across Canada. I've received hundreds of emails and letters and phone calls of encouragement from people at very many different levels and many walks of life across Canada," he said.
"We're trying to assemble the best team possible and, before making any formal announcement, I want to make sure I have a full team in place."
In counterpoint to Boivin's support for Topp, Mulcair added: "I can tell you ... that I have the support of a very large majority of my Quebec caucus and I'm very thankful for that and honoured by that support."
The Quebec caucus of 59 MPs accounts for more than half the 103 seats the NDP won in the May 2 election.
Interim leader Nycole Turmel is expected to announce during the three-day caucus retreat rules for MPs who decide to toss their hats in the leadership ring. Among other things, she is expected to insist that candidates give up their shadow cabinet roles.
That could rob the NDP of some of its top performers on some of the most crucial files during the fall and winter sitting of Parliament.
Mulcair, for instance, is deputy leader and House leader. Others considering a leadership bid include finance critic Peggy Nash, industry critic and caucus chairman Peter Julian, health critic and deputy leader Libby Davies, foreign affairs critic Paul Dewar and environment critic Megan Leslie.
British Columbia MP Nathan Cullen, who is considering running, said critics should have to give up their roles if they become leadership candidates.
"You want a fair fight, you want a good strong conversation and you want no one given any advantage," said Cullen, associate natural resources critic.
He added that allowing candidates to keep high-profile shadow cabinet posts would "make it unfair to anybody who's coming from outside of caucus or from within caucus without a special role."
Several other potential contenders, including Mulcair, suggested it might be impossible to simultaneously fulfil their critics' duties while campaigning for leader.
"How could I do both?" said Leslie. "I would see it as a bit of a blessing to have the freedom to go around the country and engage with people at the grassroots."
Even without some of their best performers in the Commons, with leadership camps forming within caucus and candidates potentially sniping at each other and staking out contradictory positions, New Democrats insisted they can still mount an effective opposition.
"We do have a strong caucus," said Quebec caucus chairman Guy Caron.
"We have plenty of excellent people who won't necessarily be involved in the race, who'll be completing these tasks and working with our current interim leader to make sure that the Harper government will be held to account."
Caucus will be asked Wednesday to finalize a strategy for the first year of a four-year plan for making the leap from opposition to government.
The strategy is aimed at ensuring the NDP mounts an effective opposition in Parliament and continues to consolidate and build on the support the party received from various groups -- ethnic communities, young people, women, Quebec nationalists -- on May 2.
The parliamentary strategy includes not only holding the government to account but attempting to set the agenda by getting out ahead of the Conservatives on key policy issues and hitting back swiftly and hard when attacked by the Tories.
The latter was already on display Tuesday when Tory MP Jacques Gourd crashed the NDP retreat. He arrived to tell reporters that he's filed a complaint to the Commons' board of internal economy about the possibility that New Democrat MPs have been using their constituency offices to sign up new party members.
The NDP instantly dispatched one of its Quebec MPs, Alexandre Boulerice, to counter Gourd's charge. He said the tactic suggests the Tories have no intention of being more civil and less partisan in the Commons.
"I think it's old politics, I think it's cheap politics and not the kind of politics the NDP want to do," Boulerice said.
Despite the tensions that are emerging between the Mulcair and Topp camps, Boulerice and other MPs maintained the leadership race won't strain the civility New Democrats have been trying to inject into politics.
"You know, we are a big family. We are all social democrats and most of the time in the past the NDP leadership race was really friendly and we are always united after that. So I don't think it's going to be a big deal for us," Boulerice said.
Of course, the stakes have never been so high in an NDP leadership race. Candidates in the past were vying to become leader of the third or fourth party, not leader of the Opposition and potential next prime minister.
Still, Leslie and Cullen both said they've personally talked to all potential contenders and all have sworn to keep the contest civil and respectful.
Brad Lavigne, Turmel's principal secretary, said New Democrats are determined to avoid the mistake made by the Liberals and Conservatives in the past, allowing their leadership races to tear their parties apart.