After the worst defeat in their storied history, federal Liberals are putting on a brave face as they set out to find new leadership to save their party from becoming a footnote on Parliament Hill.

On Tuesday, the national board of the federal Liberal Party re-jigged party rules to put off finding Michael Ignatieff's permanent successor.

The board said there will be a virtual convention in June to amend the constitution, so the party can wait beyond the mandated six months to find a new leader. Many Liberals are calling for a period of one to two years with an interim leader, so the party can make the right choice on who will lead them into the next election.

It also set out rules for the interim leader, saying he or she must have the support of the majority of both elected MPs and senators.

The plan also stipulates the interim leader must be bilingual, which rules out veteran MPs like Ralph Goodale and Wayne Easter, and that the interim leader must not pursue any discussions of a merger between the Liberals and the NDP.

The interim leader must also not run to become permanent leader.

Those rules appear to be aimed at keeping Toronto MP Bob Rae, who mused on Election Day about a combined left, from becoming interim leader.

Rae, who is fluent in both languages, has not ruled out running to replace Ignatieff.

Widely considered a top performer in question period and with previous leader experience as the head of the Ontario NDP, Rae was initially pegged by many as an obvious short-term solution for the Liberals.

Many others in the 34-MP Liberal caucus are also likely ruled out by the new rules.

Those considered frontrunners for the permanent job, such as Justin Trudeau, Dominic LeBlanc, David McGuinty and Marc Garneau, are unlikely to want the interim job unless they put any future ambitions aside.

That leaves Liberals with only a few choices left among their bilingual MPs: Scott Brison, John McCallum, Geoff Regan, Joyce Murray or Mauril Belanger.

A time for renewal

Last week's electoral bloodbath has led to an existential crisis for the Liberals, who were once known as Canada's "natural governing party."

They find themselves being squeezed by the NDP on the left and the Conservatives on the right, with many suggesting it's time for the two parties to consider merging.

Both current MPs and former MPs are brushing aside merger talk and are calling for a period of renewal, saying that Canada needs a strong centralist party.

Part of that renewal is figuring out what exactly went wrong on Election Day.

Former Liberal MP Gerard Kennedy said the party is "humbled by the election . . . and the parties that did better.

"There's a yearning there we didn't capture and the NDP did for the present moment," he told CTV's Power Play.

He suggested the party did not put enough "solutions out there for specific issues" during the campaign.

Brison, a Nova Scotia MP, said the party needs a hard look at policy, something it didn't do after the last leadership race in 2006.

He said the Liberals need to re-engage with the grassroots of their party.

But Brison said that the two-year Conservative attack-ad campaign on Ignatieff can't be overlooked.

"The die was cast by two years of negative ads . . . they were very successful," he said. "He was effectively torpedoed before the campaign even began."

He said while on the campaign trail he heard many Canadians repeating some of the Conservatives attacks on Ignatieff.

Another Liberal heavyweight MP who lost his job, Mark Holland, said the party must look beyond its leader.

"It's not about quick fixes, it's not about one person who is going to paint over everything and make it OK," he told Power Play. "The Liberal Party has a choice; it either makes reforms and it changes . . . or we've got even darker days ahead of us."

John Manley, a former Liberal finance and foreign affairs minister, said the party has to get away from the "natural governing party" attitude.

"There was an attitude and voters can smell that sense of entitlement a mile away and I think the party failed to really tackle that," Manley told Power Play.

"You have to have some core beliefs and know what they are. I happen to believe there's a big piece of the centre of Canadian politics that is up for grabs and I define that centre as being economically prudent . . . but socially progressive."