A purported frontrunner in the impending NDP leadership race says he believes the momentum that propelled the party to unprecedented success in May will not be broken by Jack Layton's death.

Party president Brian Topp, who admits he's considering a leadership run to succeed Layton, says voters have recognized there is a clear and viable alternative to the status quo.

Layton died from cancer last Monday. The attention paid over the past week of tributes to his politics and legacy will have lasting impact, Topp said, "because what happened this week was a wonderful look at something new in Canadian politics that more and more Canadians want."

"Conservatives have had things mostly their own way in much of the democratic world in recent years, by following a playbook that is about voter suppression, micro-targeting, and appealing to people's anger and fear," Topp said in an email interview Sunday.

"Jack Layton will be an enduringly important leader among social democrats, I think, because he put his finger on an alternative that more and more Canadians support -- set out, inspiringly I think, in his final letter."

Layton's death sparked a weeklong outpouring of public tributes and adoration while his body lay in state in Ottawa and in repose in Toronto.

It was capped by a state funeral in Toronto on Saturday that had all the verve of a campaign rally, led by Stephen Lewis, former Ontario NDP leader and one-time Canadian ambassador to the United Nations, who delivered a eulogy extolling the virtues of Layton's social democratic vision.

Topp and Layton's wife, MP Olivia Chow, were among those who helped the dying leader pen a final goodbye to Canadians two days before he died.

In it, Layton recommended the party hold a leadership vote as early as possible in the New Year.

He urged his colleagues to continue what he started and he preached a positive approach, now-famously declaring "love is better than anger. Hope is better than fear. Optimism is better than despair."

"No one will replace Jack. But we can continue his work," said Topp.

"That will be about carrying forward his approach to politics.

It will be about continuing to focus on getting things done that matter to people. It will be about compellingly representing the people of Quebec.

"And it will be about persuading Canadians in other provinces that the next federal government can be a new, better, progressive and truly national one."

With an emotional week behind them, the party's national director, Brad Lavigne, suggested that work starts first thing Monday, as the staff of the Opposition Leader's Office move into new digs under interim leader Nycole Turmel.

"We honour Jack's legacy by rolling up our sleeves and getting down to work, first thing Monday morning," Lavigne said by email Sunday.

"The caucus and staff are stronger, more united and have more resolve then ever before."

Layton's predecessor, Alexa McDonough, said Saturday that Layton's ability to connect with Quebecers and tap into their social-democratic sentiments were key to his success.

And she said they will be key to any future success of those who come after him. People are already picking up where Layton left off in terms of his nation-building, she said in an interview.

"He had spent his entire adult life influencing people to take up the social democratic cause," McDonough said.

"You can already see that he's reached beyond the grave in terms of challenging people to carry on."

McDonough said Layton managed to tap into something that none of his predecessors, herself included, were able to do.

Part of that success, she said, was Layton's "cachet" at having been born in Quebec and his ability to speak French fluently.

But there was something even more important to his ability to connect with Quebecers in their own language.

"He also understood at a really deep level that Quebecers were, at the very core, social democrats," McDonough said.

"So there needed to be a marriage there take place between the social democratic sentiments of Quebecers and the social democratic sentiments of the rest of Canada."

Ultimately, she said, it was Layton's "love and affection" for Quebec and his ability to share that feeling with the larger Canadian family that really resonated with all Canadians and propelled the party to No. 2 in the House of Commons for the first time.

The Bloc Quebecois was reduced to just four seats on May 2, losing its official party status -- and the resources that went with it -- in the process.

Meanwhile, Party Quebecois leader Pauline Marois has been struggling with internal strife within her own caucus, losing five provincial members in the process.

The NDP surged to 103 seats -- 59 in Quebec -- in a campaign marked by Layton's cane-waving rallies, where he preached optimism and civility in politics.

Topp cautions that Quebec's sovereigntist movement is "never to be underestimated."

"But I think the overwhelming majority of Quebecers are tired of being divided around the old debates between Liberals and PQistes/Blocistes," he said. "Quebecers want to live in a country in which they are understood and respected.

"We have some unfinished business to attend to in that regard, when we can be certain of success. Provided that is understood, both federally and provincially I think there is a strong mood in the province to turn the page on both the reds and the blues, and to get behind new people with new ideas."

"People like, say, New Democrats."

Topp says he agrees with Northern Ontario MP Charlie Angus "that the time will come soon to stop shedding tears for our friend and leader, Jack, and to act on his call to carry forward our party's work."

Talk will now inevitably turn in earnest to Layton's potential successor -- a subject Lavigne considered still taboo on Sunday, but not Topp, who is fluently bilingual and is said to have been encouraged to run by Layton himself.

"I believe there are a number of credible potential candidates to carry forward Jack's work as leader," Topp said. "I don't doubt all are having family days today, after yesterday's funeral, and are beginning to think about those questions, as I am."

Montreal MP Thomas Mulcair, Layton's deputy leader, is widely considered to have a serious shot at taking Layton's place. Other names include former Manitoba premier Gary Doer, former Nova Scotia NDP leader and newly elected MP Robert Chisholm, and veteran MPs Libby Davies and Paul Dewar.

Still, McDonough said, whether the New Democrats could find another leader to continue the party's recent successes without Layton remains to be seen.

"What the party can do from here on in, we'll see unfold," McDonough said.

"(But) the challenge that he has put to people to carry on that dream and continue with that work has already been taken up with a vengeance. You can see it all over the country."