A spasm of media attention — a rarity in Liberal circles since their devastating defeat in the 2011 election — followed Trudeau all day in hopes he might confirm that yes, indeed, he intends to seek the job his famous father once held.
Some of his critics question whether Trudeau has the gravitas or depth to be prime minister. That's not the job description, his supporters maintain.
They say what's at stake is the survival of the once-mighty Liberal party — a job that calls for a leader who can prevent the party from sinking into oblivion, who can capture the public's imagination, attract new blood and rebuild from the ground up.
Trudeau undeniably has attention-grabbing talent in spades. He has been the party's top fundraising draw for years and attracts fawning fans wherever he goes. A charity boxing match last winter, in which Trudeau bested Conservative Sen. Patrick Brazeau, received wall-to-wall coverage.
Since the 2011 election, the tiny Liberal caucus has met weekly in an out-of-the-way room in the basement of Parliament's Centre Block, attracting few if any reporters.
On Wednesday, a phalanx of television cameras and outstretched microphones besieged Liberals outside their caucus meeting amid reports that he'll announce his candidacy Tuesday in his Montreal riding of Papineau.
"Thank you very much for your interest," a smiling Trudeau said on his way out of the meeting.
"I'm pleased to hear all the buzz and all the interest in the Liberal party's fortunes. But I have nothing further today ... I promise I will let you know when I have something to announce."
Trudeau's crowd-pleasing, attention-grabbing charisma has already made him the prohibitive favourite in the leadership race, which doesn't officially begin until November and won't wrap up until April 14.
However, some Liberals are waiting to see if there's more to Trudeau than a pretty face with boyish charm, an engaging manner and a famous last name. They want to see if he can demonstrate the depth, vision and strategic smarts to bring the once-mighty Liberal party back from the brink of extinction and, eventually one day, back into power.
While his undisputed crowd-pleasing talent is touted as the most important qualification for a party struggling for its very survival, those close to Trudeau are well aware that he must also disprove critics who maintain he's an intellectual lightweight coasting on the coattails of his late father, Liberal icon and former prime minister Pierre Trudeau.
His strategists argue Trudeau's intellect is under-estimated, noting that he has obtained two university degrees: a bachelor of arts and a bachelor of education.
And they maintain he's already demonstrated strategic smarts by insisting on climbing the political ladder the hard way, from the bottom up. He turned down an opportunity to run in a safe Liberal riding in 2007, choosing instead to run in a contested nomination in Papineau, a riding held at the time by the Bloc Quebecois.
Although he's never held any senior shadow cabinet posts, Toronto-area MP John McCallum said Wednesday he believes Trudeau is ready to be leader.
"He's young but there are lots of young leaders and I think it's not a bad time for a change of generation."
That said, McCallum said he thinks it would be best for the party if Trudeau is tested in a vigorous leadership race with three or four strong contenders. But he's concerned that won't happen, given Trudeau's huge presumed lead.
"I think there's a risk that his candidacy will scare off others and that we could be heading for a coronation," McCallum said.
"There are other names out there as possibilities and those people won't necessarily be discouraged by Justin's candidacy. But there is a risk that some good candidates will think he's unbeatable and therefore won't participate."
A number of potential rivals, including Liberal House leader and fellow Montreal MP Marc Garneau and Ottawa MP David McGuinty, declined to comment Wednesday.
But Montreal MP Denis Coderre, who has promised to announce on Nov. 9 whether he'll run for the leadership or Montreal mayor, said he's not deterred by Trudeau's name recognition.
"Oh, Coderre's a big name too," he quipped.
Coderre predicted the Liberals' path to victory will run through Quebec, where the NDP swept 59 of 75 seats in the last election. In that regard, he said the Liberal party's tradition of alternating French and English leaders will be important.
"I think it might be the turn also for a francophone. (Alternance) has always served well the party."
Vancouver MP Joyce Murray said she's put together an exploratory committee to see if she has sufficient support to mount a credible national leadership campaign. She said Trudeau's decision "doesn't have any bearing on my decision."
"I reached a conclusion that I have something important to offer, a contribution to make to our party and to the country and an appetite to do that."
Toronto lawyer and one-time Liberal candidate Deborah Coyne, mother of Trudeau's step-sister, has announced her intention to seek the leadership, as has Manitoba paramedic Shane Geschiere. A host of others are pondering potential bids.