For most of 2016, public support for Justin Trudeau's Liberals appeared to be invulnerable to the slings and arrows of the opposition. But a series of recent polls suggests some of the attacks might be leaving a mark — though the extent of the damage isn't entirely clear just yet.

The first indication of Trudeau's troubles came a little over a week ago in a Forum Research poll conducted for the Toronto Star. It was the first survey done in the aftermath of the government's decision to approve two oil pipelines and reject a third. It was also taken as the controversy surrounding the prime minister's attendance at $1,500-per-ticket fundraising events was in full tilt.

The poll suggested support for the Liberals had fallen to 42 per cent from 51 per cent, a statistically significant drop of nine points compared to Forum's November survey. The poll also showed Trudeau's approval rating dropping by seven points to 51 per cent.

Now, three polls published over the past few days provide some indication as to whether Forum's findings were meaningful. But the signals are a bit mixed.

The Angus Reid Institute (ARI) found that Trudeau's approval rating had fallen 10 points to 55 per cent since mid-September, while CROP showed the Liberals' support in Quebec sliding by five points since November.

Both Forum and ARI recorded Trudeau's ratings falling significantly in B.C., Ontario and Quebec.

Not a clear-cut case

But a new Abacus Data poll doesn't show any major decrease in support for the Liberals. The survey found the Liberals down just two points over the same period as Forum's polling, to 44 per cent. That shift in support wasn't statistically significant. In fact, Abacus has registered Liberal support at between 44 and 46 per cent in its past six polls going back to May.

Abacus also found the Liberals' support holding steady in Ontario and Quebec. It was down only marginally in B.C.

Interim Conservative Leader Rona Ambrose has called the Liberal fundraising controversy an 'ethical mess.' (Sean Kilpatrick/Canadian Press)

Additionally, the Liberals' numbers remain high. Both Forum and Abacus put Liberal support above where it was on election night in 2015. CROP puts the Liberals almost 20 points up in Quebec over their election performance.

Both Forum and ARI still have a majority of Canadians approving of Trudeau's performance as prime minister — a level of approval that Stephen Harper, his predecessor, rarely achieved during his tenure in the job.

Nevertheless, the apparent softness in Trudeau's numbers suggests things could get worse for the prime minister before they get better.

The cost of fundraising

Abacus asked Canadians about some of the Liberals' recent decisions and controversies, including pipeline approvals, the prime minister's fundraising activities and the government's handling of electoral reform.

Over 40 per cent of Canadians said they hadn't heard of the issues related to the electoral reform file and about another 30 per cent said it had no impact on their view of the government.

But the poll suggests the fundraising controversy could be an ongoing and damaging problem for Trudeau. While 31 per cent of respondents said they hadn't heard about it and another 32 per cent said it made no difference to them, 27 per cent said it made them feel worse about the Trudeau government. Just nine per cent said it made them feel better.

Abacus found that 15 per cent of "Liberal losable voters" (those who would vote for the Liberals today but would also consider voting for another party) said it made them feel worse about the government.

Among those who are "Liberal winnable voters" (those who would not vote for the Liberals today but could consider it), the controversy made them view the government worse rather than better by a margin of three to one.

Pipelines to hurt Liberals in B.C.?

While the Abacus poll found the government's decision on pipelines was a net positive one nationwide, a negative impact could be felt in B.C.

The decision to approve an expansion of Trans Mountain, a pipeline carrying oil products from Alberta to Burnaby, B.C., was seen negatively in the province by a margin of almost two to one (though rejecting Northern Gateway, a pipeline that would have run to a port in northern B.C., was seen positively by a similar margin).

Many folks in B.C. aren't happy the federal government approved the $6.8-billion expansion of the Trans Mountain pipeline, which carries crude oil from near Edmonton to the Vancouver area to be loaded on tankers and shipped overseas.

Both Abacus and Forum saw drops in Liberal support in B.C., but they were within the margins of error for the small regional sample sizes. Forum's 16-point decrease in Trudeau's approval in B.C. was statistically significant, however.

ARI also found Trudeau's approval rating down in B.C., though that still put it at 56 per cent.

These polls suggest Trudeau and the Liberals probably have suffered a hit in public opinion over the last month and point to the possibility they could see their support drop further due to the $1,500-per-ticket fundraising controversy and the pipeline issue in B.C.

But the trends are muddled. And with the party leading the Conservatives by between eight and 14 points in the Forum and Abacus polls and its leader still seen positively by a majority of Canadians, the Liberals might feel they have little reason to panic — yet.

The Forum Research poll for the Toronto Star interviewed 1,304 adult Canadians between Dec. 6 and 7, 2016, via interactive voice response. A probabilistic sample of this size would yield a margin of error of three percentage points, 19 times out of 20.

The Angus Reid Institute poll interviewed 5,128 adult Canadians between Dec. 5 and 12, 2016, via the Internet. A probabilistic sample of this size would yield a margin of error of two percentage points, 19 times out of 20.

The CROP poll interviewed 1,000 adult Quebecers between Dec. 7 and 12, 2016, via the Internet. A probabilistic sample of this size would yield a margin of error of three percentage points, 19 times out of 20.

The Abacus Data poll interviewed 1,848 adult Canadians between Dec. 12 and 14, 2016, via the Internet. A probabilistic sample of this size would yield a margin of error of two percentage points, 19 times out of 20.