The battle lines for the next election could very well be taking shape as a new poll suggests Justin Trudeau's Liberals have solidified their lead over the governing Conservatives.
Taken in the aftermath of last week's four federal by-elections, The Canadian Press Harris-Decima survey indicates Liberal support is at 34 per cent, down slightly from the 37 per cent recorded the week before.
The Conservatives are hovering at a consistent 26 per cent, while New Democrats putter along at 24 per cent.
Pollster Allan Gregg says the latest numbers not only reinforce the split by-election results last Monday, but demonstrate a significant shift is under way in terms of both the Conservatives and Liberals.
"What you have is two things happening at the same time," said Gregg. "You have the Liberal core constituency is coming back to where they always were and over the last year you've seen a fairly significant erosion of the Conservatives' core constituency."
He says traditional Liberals – the so-called professional class and women – are returning to the fold, while stalwart Conservatives – men and rural voters – appear to be wavering and expressing disappointment with the Harper government.
Gregg says some of the disenchantment might be related to the Senate spending scandal, but he says he believes the trend is more long-term and could lead into the next election in 2015.
Revelations of illegitimate expense claims, an RCMP investigation and allegations of a cover-up in the Prime Minister's Office involving Stephen Harper's former chief of staff and ex-Conservative senator Mike Duffy have rocked the government on a daily basis since the spring.
Liberal Leader Justin Trudeau told CTV's Question Period on Sunday "there's reason to be optimistic" and that voters are connecting with his party's message of support for the middle class and transparency in government.
The public is frustrated, but he cautioned there's still a long way to go before the next election.
"What we have to be careful of is not to read too much into by-elections [that are] two years away from any general election, but certainly we're pleased with the kind of response we're getting from right across the country," Trudeau said.
The latest poll involved 2,000 people and is considered accurate plus or minus 3.1 per cent 19 times out of 20.
There is a bit of a silver lining in some of the regional numbers for the NDP, Gregg said.
Opposition leader Thomas Mulcair remains a formidable political figure in Quebec, the NDP's base of support, and the party continues to poll above its traditional range of 18-20 per cent.
But sustained returns like this could force New Democrats on to a different political tack, perhaps away from the moderate middle ground they've tried to cultivate, Gregg said.
"What the numbers say to the NDP is that they are going to have to differentiate themselves if the Liberals look like the most obvious alternative to the Conservatives in an environment where the electorate has said two things; one traditional Liberals have said I'm going home and traditional Conservatives are saying I'm pretty disappointed with these guys," he said.
The latest survey also comes against a backdrop of Conservative MP Michael Chong's bid to reform the Canada Elections Act and the Parliament of Canada Act.
On Thursday, he will introduce a private member's bill that would mean leaders serve at the pleasure of caucus, not the party. It would also empower caucus to expel undesirable MPs and take away the leader's right to sign nomination papers, giving the authority to local riding associations.