Polls suggest that François Legault's Coalition Avenir Québec could set a new record in the Oct. 1 election — by forming a majority government with the smallest share of the popular vote of any majority government in the province's history.

It's the kind of thing that could rewrite the conventional wisdom on electoral politics in Quebec. How much of the vote does a party really need to have a good shot at a majority?

We may be about to find out. As of Aug. 29, when CBC's Quebec Poll Tracker was last updated, the CAQ had an 81 per cent chance of winning a majority in an election held immediately — even though the party is estimated to have just 36.6 per cent support.

Of the five pollsters who have reported survey results since the campaign kicked off, four have pegged the CAQ with between 32 and 38 per cent support. (The outlier was Forum, registering the CAQ's support at 42 per cent.)

Using the Poll Tracker's seat projection methodology, the most likely outcome, if each of these polls' results were replicated on election day, would be at least 63 seats for the CAQ — the minimum threshold required for a majority government.

No party has won a majority government in Quebec with less than 38 per cent of the vote — and only once did a party manage it with less than 40 per cent of ballots cast.

Is CAQ the heir to Union Nationale?

The record-holder is the Union Nationale under Maurice Duplessis, which captured 38 per cent of the vote and 48 seats in the 1944 election, putting it just over the majority threshold in what was a 91-seat legislature at the time.

But even that election result was rather anomalous. Adélard Godbout's Liberals won the popular vote with 39.4 per cent, but fell short with just 37 seats. The reason then was the way in which Liberal and Union Nationale support was distributed in the province — a distribution not entirely dissimilar to how support for the Liberals and the CAQ is breaking down regionally (and linguistically) today.

The Union Nationale under Maurice Duplessis won a majority government in the 1944 provincial election with just 38 per cent of the vote, the lowest ever in Quebec's history. (Canadian Press)

The 1944 election had a smaller nationalist party on the ballot in the Bloc populaire (a party opposed to conscription during the Second World War) — which won 14.4 per cent of the vote and four seats — and an even smaller left-wing party in the provincial wing of the Co-operative Commonwealth Federation, which took one seat and 2.6 per cent of the vote.

It's an electoral landscape that doesn't look very different from the one in Quebec today. And the historical precedent is a positive one for Legault: the UN governed for 16 years after the 1944 election.

Francophone vote key to CAQ majority hopes

So the CAQ is in a position to win a majority government with a historically low share of the popular vote — and could even secure more than 63 seats with even less support than it currently enjoys — because of its dominance among francophones, who make up at least 65 per cent of the population in 100 of Quebec's 125 ridings.

According to the Poll Tracker, the CAQ has the support of 41 per cent of francophones. More importantly, it puts the party 19 points ahead of the Parti Québécois and 21 points ahead of the Liberals among francophones. Since the CAQ isn't facing stiff competition for its core francophone vote, it has the edge in many ridings across the province.

That core vote was key to the PQ's majority victories in 1994 and 1998 — the last elections in which a party other than the Liberals won a majority. Despite only besting the Liberals by 0.4 percentage points in 1994 — and being bested by the Liberals by 0.7 points in 1998 — the PQ won comfortable majorities in those elections thanks to its unrivalled edge among francophones.

In 1998, the Parti Québécois under Lucien Bouchard lost the popular vote but won a majority government. (Paul Chiasson/Canadian Press)

A poll conducted by CROP at the end of the 1994 campaign gave the PQ a 14-point lead over the Liberals among francophones. In 1998, a survey by SOM conducted mid-campaign put the PQ's edge among francophones at 18 points.

In both elections, there was no major third party to split the francophone vote. Mario Dumont's ADQ, the predecessor of the CAQ, took just 6.5 and 12 per cent of the vote in 1994 and 1998.

The PQ could have won a majority even with a much smaller share of the popular vote, thanks to this advantage among francophones. Its victories were not near-run things: the party finished with a majority cushion of 14 seats in 1994 and 13 seats in 1998.

What's the magic number for a minority?

A Léger poll published last week suggested that Quebecers believe the most likely outcome of the election is a minority government. That might not be an unreasonable assumption, as the CAQ is well below that 38 per cent historical threshold.

But Quebec doesn't have a lot of experience with minority governments. In fact, the province has elected minority governments only twice since the beginning of the 20th century.

And those two campaigns didn't look much like the one happening today. In 2007, Jean Charest's Liberals took just 33.1 per cent of the vote and finished only 2.3 points ahead of the ADQ. In 2012, the PQ under Pauline Marois had just 31.9 per cent of the vote and a razor-thin margin of 0.7 points over the Liberals.

More important, perhaps, is the fact that in both of those elections, the third-place finisher was not far behind: 28.4 per cent for the PQ under André Boisclair in 2007 and 27.1 per cent in 2012 for the CAQ in Legault's first campaign as leader.

The Parti Québécois under André Boisclair finished third in the 2007 provincial election, the only time the PQ has finished in that position in the popular vote in its history. (Ian Barrett/Canadian Press)

Today, the PQ under Jean-François Lisée is in third place with only 18.4 per cent support — not enough to make a significant impact.

It would take more than just a slip in CAQ support down into the low 30s to push the party into minority territory. It also probably would require an increase in support for the Parti Québécois, one that would move enough seats into the PQ's column to drop the CAQ below the 63-seat majority threshold.

It's a complicated electoral calculus, combining the CAQ's support among francophones, its lead over the Liberals and the margin between the first and third place parties. All of these variables can change between now and Oct. 1 — but if the numbers hold steady, the math looks good for Legault's shot at making history.