His willingness to confess his past proclivity for puffing pot is part of a deliberate strategy to brand the Liberal leader as a different kind of politician - one who's open and transparent to a fault, even when it might be more politic to dissemble.
It's a calculated risk that could pay big dividends or blow up in his face, Liberal insiders acknowledge.
But he's determined to make transparency a trademark of his leadership.
His voluntary admission last week that he took a pull on a joint at a dinner party three years ago — while he was an MP — wasn't the first example of Trudeau's potentially perilous frankness and it won't be the last.
During the leadership contest that crowned him last spring, Trudeau voluntarily disclosed all his sources of income, including his inheritance from his late father, former prime minister Pierre Trudeau, and more than $1 million earned on the public speaking circuit.
The fact that he continued to accept hefty speaking fees from charitable groups and educational institutions after being elected as an MP in 2008, sparked sufficient public backlash that he eventually offered to refund any group that felt it hadn't gotten its money's worth. In the end, none took him up on the offer.
As with the marijuana admission, the speaking fee controversy handed Conservative and New Democrat rivals an opportunity to jab at what they consider Trudeau's Achilles' heel: his judgment, or lack thereof.
But Liberals are gambling that the appeal of Trudeau's candour will outweigh any concerns about his behaviour.
"It's the type of leadership that (Canadians) have been waiting for," Liberal House leader Dominic LeBlanc wrote last week in a blog on the party's website as the pot controversy raged.
"Rather than duck and dodge, our leader gave straight answers to tough questions."
The commitment to transparency isn't going to be confined to the leader, however.
During a three-day caucus retreat in Prince Edward Island that begins Tuesday, Liberal MPs and senators are to be presented with a template for publicly disclosing their expenses online, starting this fall. That's in keeping with a promise made by Trudeau last spring amid the uproar over the Senate expenses scandal and it could potentially turn up some unwelcome surprises.
MPs will also be given a rundown on how the party intends to handle Trudeau's pledge to hold open nominations in every riding across the country, forgoing the leader's power to appoint candidates or protect incumbents from challenges — and risking some messy internal battles in the process.
And insiders say he'll unveil yet more proposals later this fall for making politicians more open and accountable.
The emphasis on transparency is aimed at contrasting Trudeau's Liberals with what they claim are Prime Minister Stephen Harper's ethically challenged, tightly scripted Conservatives.
Trudeau's openness about smoking marijuana, along with his call to legalize and regulate weed, has the added benefit of appealing to the young and progressive voters who might otherwise support the NDP, Liberal strategists contend.
While some voters may have qualms about the wisdom of a lawmaker openly confessing to flouting the law, Trudeau's team believes most are more concerned about economic issues and that's where they'll pass judgment on the leader's fitness to govern.
To that end, Trudeau is likely to unveil some specific proposals this fall in a bid to put some meat on the bones of his declared top priority: improving the fortunes of the struggling middle class.
Major platform planks will await the election in 2015 but Liberal finance critic Scott Brison says the plight of middle-class Canadians is too urgent to ignore in the meantime.
"We're not just waiting until the next election," he says.
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