The Liberal leader is seen as the federal leader who most cares about Canadians and shares their values but is relatively inexperienced and weak on economic issues; the prime minister is seen as the most experienced leader and most capable economic manager, but less caring and less in tune with Canadians' values.
NDP Leader Tom Mulcair appears to be getting squeezed out of the equation, trailing both Trudeau and Harper in popularity and in leadership attributes, the poll suggests.
The Canadian Press Harris-Decima survey was released Thursday, just as federal Liberals were wrapping up a three-day caucus retreat in Prince Edward Island, at which Trudeau played up his caring and sharing side but shunned offering any details of his economic policies.
At a wrap-up news conference, Trudeau said the biggest challenge facing Liberals as the party builds toward the next election in 2015 is "convincing Canadians that politics can be a positive force in their lives ... free from the kind of cynicism that is all-encompassing in politics these days."
He contrasted his commitment to transparency and openness with what he depicted as the Harper government's tendency to "mislead Canadians, to spin its way out of problems, to hide from very serious moral and ethical lapses."
"Canadians are willing to think the least of their politicians and we in the Liberal party need to, by working with Canadians, by connecting with them, by demonstrating that we trust Canadians, restore a modicum of trust for politicians. And that's our big challenge."
On that score, the poll suggests Trudeau is already striking a chord with Canadians.
Respondents gave him the highest approval rating, with 54 per cent saying they have a favourable impression of Trudeau, versus 31 per cent who have an unfavourable impression.
The rating for Harper was almost exactly reversed: 56 per cent unfavourable, 36 per cent favourable. Impressions of Mulcair were almost evenly split, 36 per cent favourable, 30 per cent unfavourable.
Thirty-three per cent said Trudeau would make the best prime minister, compared with 29 per cent for Harper and 14 per cent for Mulcair.
Asked which leader "shares your values," 33 per cent of respondents picked Trudeau, 24 per cent Harper and 17 per cent Mulcair.
Asked which leader "cares about people like you," 32 per cent chose Trudeau, 21 per cent Harper and 17 per cent Mulcair.
Harper and Trudeau were tied on the question of who would best represent Canada on the world stage, with 32 per cent each. Only 14 per cent picked Mulcair.
But on questions about economic management and fitness to govern, Trudeau lost the advantage to Harper.
Thirty-nine per cent chose Harper as the leader most capable of tackling economic issues, while just 20 per cent picked Trudeau and 15 per cent Mulcair.
Twenty-eight per cent said Harper demonstrates the best judgment, compared with 24 per cent for Trudeau and 17 per cent for Mulcair.
And fully 43 per cent picked Harper as the leader with the type of experience to be prime minister, versus 21 per cent who chose Trudeau and only 15 per cent who picked Mulcair.
On most questions, Mulcair scored better in Quebec, the NDP's base, than elsewhere. Trudeau's popularity was relatively consistent across regions, more pronounced among those under age 35, while Harper's was most pronounced west of Quebec and among those over age 65.
The popularity of the three main federal party leaders and Canadians' impressions of their various leadership attributes have changed little since last April, when Trudeau's ascension the Liberal throne shook up the national political landscape.
That suggests Trudeau has not been hurt by his recent admission that he smoked marijuana at least once after becoming an MP.
At the same time, it suggests he's done little to reassure Canadians that he's got the experience or judgment to manage the economy. Although he's made improving the lot of middle-class families the centrepiece of his leadership, Trudeau has not so far spelled out how he intends to help them.
At the caucus retreat, he resolutely refused to be rushed into unveiling his economic policies, arguing that he wants to consult extensively with experts and Canadians first before coming up with an economic platform in time for the 2015 election.
"We'll be holding roundtables, meetings, town halls, information sessions. We will continue to work in a robust, transparent way to make sure that we build the solutions that Canadians deserve," he said Thursday.
Trudeau said one of the Liberals' big challenges is "to get this government to actually realize that they haven't done a good job where it counts on the economy."
However, the poll suggests the bigger challenge will be to get Canadians to buy into his assertion that the Conservatives have been lousy economic managers.
Harris Decima surveyed 1,010 people by telephone Aug. 22-25, and says the results are accurate to within plus or minus 3.1 percentage points, 19 times out of 20.
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