Justin Trudeau's Liberals continue to enjoy more support today than they did in the 2015 federal election and have yet to see their poll numbers take a negative turn. But as the government enters the second year of its four-year mandate, it's making decisions that have the potential to disappoint some of its new supporters.

Over the last quarter, the Liberals have averaged 47.9 per cent support in national polls, a marginal gain over the previous quarter but up 8.4 points compared to election night. The Conservatives have averaged 28.7 per cent, down 3.2 points from the election, while the New Democrats have slipped 7.1 points to just 12.6 per cent support nationwide.

While the shifts in support since the previous quarter are insignificant, they are nonetheless consistent. The Conservatives have nudged downwards in two quarters and this is the fourth consecutive quarter in which support for the NDP has dropped. The Liberals have been the beneficiaries, as they have made gains in every quarter since last year's election.

The lack of a permanent leader in three of the four opposition parties — Elizabeth May of the Green Party is the sole exception — could be making things easier for the Liberals, but it's not a given that leaderless opposition parties always take a big hit in the polls.

After the death of Jack Layton in August 2011, the New Democrats didn't see their support fall very much. The leaderless Liberals, following the resignation of Michael Ignatieff that same year, significantly improved their position in the polls long before Trudeau was selected as their new leader. Today's New Democrats and Conservatives are underperforming compared to the leaderless opposition parties of 2011-13.

Can Liberals hold gains in B.C.?

Nowhere have the Liberals seen a notable shift in support since the last quarter, but that just means the party continues to hold on to the gains it made in the immediate aftermath of the last election — the so-called honeymoon.

The biggest gains have been in Quebec, where the Liberals averaged 50.4 per cent over the past three months. That's up nearly 15 points from their election performance, when the party won 40 of 78 seats in the province.

​The Liberals also continue to lead comfortably in B.C., averaging 45.8 per cent over the last quarter. But those gains, which came primarily from the New Democrats, could be at some risk with the government's recent decision to approve the Trans Mountain pipeline.

Opposition to the project is greatest in B.C., and the issue could be what New Democrats need to claw back some of the support among progressives they've lost to the Liberals over the last year.

The Liberals' handling of the electoral reform file — an issue that polls tend to show is more important to progressives — could also jeopardize some of the gains they've made nationwide (the party is still up around six points in Alberta, the Prairies and Ontario).

Conservatives at their floor

Support for the Conservatives under interim Leader Rona Ambrose has held firm throughout the country over the last quarter, keeping the party at what might be its hard floor of support.

The Conservatives are down almost uniformly in most parts of Canada since the election. They have slipped 3.1 points in Alberta, 3.5 points in both Ontario and Quebec, 3.6 points in B.C. and 4.4 points in Saskatchewan and Manitoba.

The party still holds a lead in Alberta, however, with 56.5 per cent, and is polling only a few points behind the Liberals in the Prairies.

In Atlantic Canada, the Conservatives have seen their support increase slightly. But the party won no seats in the region with 19 per cent support last year. The improvement now to 20.3 per cent suggests the Conservatives might have hit their floor on the East Coast in 2015.

NDP troubles in Quebec

The New Democrats have lost support in every region since the last quarter, with the exception of the Prairies, but the party led by Tom Mulcair has suffered its worst losses in his home province of Quebec.

The polls have gone from bad to worse for the NDP in the province that almost single-handedly propelled the party to Official Opposition in 2011. The New Democrats have averaged 13.9 per cent support in Quebec over the past three months, putting them in third place and only narrowly ahead of the Conservatives. Even after their initial post-election slump, the NDP has shed one or two points' worth of support in each of the past three quarters in Quebec.

The NDP polls best in B.C., where the party is at 17 per cent. But that's still nine points lower than the party's support there last year.

Greens improve in B.C.

The Greens routinely poll better than they perform on election night. The party is averaging 5.4 per cent support nationwide, two points up on its 2015 election result.

The base for the Green Party remains B.C. With 10 per cent support, the Greens are about twice as strong on the West Coast as they are anywhere else in the country. The Liberals' pipeline decision could help boost the Greens in B.C., as well as a provincial election in May in which the Greens have decent prospects of winning more than the one seat they currently hold.

Status quo for the Bloc

The Bloc Québécois is in second place in Quebec with 16.8 per cent support, down nearly three points from its election performance. But the Bloc appears to be stuck. In the past three quarters, interim Leader Rhéal Fortin's party has gained two points, lost two points and gained two points again.

This article reviews trends in national public opinion surveys, and includes all polls conducted and published by different pollsters between Sept. 1 and Nov. 30, 2016. Methodology, sample size and margin of error, if one can be stated, vary from survey to survey and have not been individually verified.