The Liberals have come under fire for their proposed changes to the tax system from the opposition, small business owners, doctors and even members of their own caucus. But it's had no impact on their standing in the polls.

Instead, the Liberals are more popular today than they were on election day almost two years ago.

And their support among the wealthiest Canadians — those likely to be impacted most by the changes — appears to have held steady over the summer.

The Liberals sit at 41.5 per cent support, according to the latest tally of the CBC Poll Tracker, an aggregation of all publicly available polling data, weighted by date, sample size and the track record of polling firms. That puts the Liberals roughly two points ahead of where they were on election night in October 2015.

The Conservatives under Andrew Scheer have 30.9 per cent, down about one point since the election, while the New Democrats have slipped four points to 15.8 per cent.

The polling conducted over the past few weeks has been very consistent. Nanos Research, Campaign Research, Abacus Data and Mainstreet Research have all put the Liberals between 41 and 43 per cent, with the Conservatives between 30 and 32 per cent and the NDP between 15 and 17 per cent.

These kinds of numbers would likely expand the Liberals' majority, perhaps giving them some 200 seats, up from the 184 seats the party won in the last election.

This is almost entirely due to the shifting political landscape in Quebec, where the Liberals have 42.3 per cent support — up seven points from 2015. The NDP has dropped nine points in the province to 16.3 per cent, putting the party's 16 seats in Quebec at serious risk.

If an election were held today, the Liberals would have decent odds of winning all of them, more than making up for any losses the party could suffer in Ontario and Atlantic Canada, where their position relative to the Conservatives has worsened slightly since 2015.

No discernible impact from tax changes

The polls suggest the raging debates over Finance Minister Bill Morneau's proposed tax changes — which look to end the practice of income sprinkling and limit the ability of Canadians to save money through their incorporated businesses — have had no real impact on public opinion.

Compared to the surveys conducted by the three pollsters who were in the field just before Morneau announced the government's proposals (Nanos, Campaign and Abacus), support for the Liberals has actually increased by an average of two points.

The shifts recorded by these three pollsters are within the margin of error and not necessarily indicative of any real movement in voting intentions over the summer, but certainly argue against the Liberals having taken any hit.

Conservative Leader Andrew Scheer has grilled Trudeau over the proposed tax changes in the House of Commons. (Justin Tang/Canadian Press)

Additionally, the polling by Campaign suggests the views of the wealthiest Canadians have not moved either. Among those earning $100,000 or more, the Liberals had 44 per cent support — unchanged from July and up two points from June.

This could be in part because few Canadians are paying attention to the debate. An Ipsos/Global News poll found just eight per cent of all Canadians surveyed are following the issue closely. That rose to just 10 per cent among those making $100,000 or more.

The NDP's unknowns

While the Liberals have yet to take a hit on their right flank — and the Conservatives may believe their opposition to the tax changes could yet be a political winner for them, if only they can raise Canadians' awareness — they have also done well on their left.

Abacus found that 56 per cent of Canadians describing themselves as on the left of the political spectrum would vote for the Liberals, 32 points ahead of the NDP.

That the New Democrats are without a permanent leader is undoubtedly a factor in their drooping poll numbers. The replacement of Tom Mulcair will be announced next month.

But regaining support in Quebec will be key for the NDP. That is where the party has suffered the steepest drop in support, a serious problem in a province that is responsible for the largest cohort of the party's caucus in Ottawa.

Holding Quebec or gaining elsewhere?

It's unlikely that any of the four candidates in the running for the leadership (Ontario MP Charlie Angus, Manitoba MP Niki Ashton, Quebec MP Guy Caron and Ontario MPP Jagmeet Singh) will have an immediate positive impact on the NDP's fortunes in Quebec.

A Léger poll recently found that no other leader would do better than Mulcair, who gave the party 19 per cent support in the province. Caron did the best among the contenders, reducing the NDP's support by just three points. But Singh, one of the front-runners, dropped it down to just 11 per cent.

While the NDP would be at risk of losing anywhere from half to all of its Quebec seats at the 19 per cent mark, dropping to 11 per cent would put the party below where it was in the 2008 election, when it won only one seat in the province (Mulcair's seat).

Candidates for the NDP leadership, from left to right: Jagmeet Singh, Charlie Angus, Guy Caron and Niki Ashton. (Darryl Dyck/Canadian Press)

But Singh could help the New Democrats in other parts of the country. Just as Caron, a native son, might do best in Quebec, Singh could help boost the party's standing in Sikh communities across Canada. There are 12 ridings in which Punjabi is the mother tongue of at least 10 per cent of the population (in Brampton, Edmonton, Calgary and Greater Vancouver).

The biggest initial obstacle, however, might be name recognition. It remains low for all of the NDP leadership candidates. As their profile increases, so could the support they bring to the party.

Until that happens, and unless the Conservatives' attacks on the government's proposed tax changes start to hit home, the Liberals will continue to hold a strong position in public opinion as the fall sitting of Parliament unfolds.