The collapse of Action démocratique in the polls raises a classic question: Is there really space on the Quebec political scene for three major parties?
Modern history has tended to demonstrate that there isn't. For Mario Dumont and his party, as they sink deeper into trouble, that might not be a nice thing to be reminded of.
So far, the tendency in Quebec for two major parties to end up facing each other has been the pattern. So-called third parties do emerge, but for them to last, they must take power within a reasonable time. And even then, nothing protects them from disappearing one day as another new third party emerges and eventually takes over.
Take the Union Nationale. It pretty much dominated politics from 1936 to 1960. Under Daniel Johnson Sr., it had its waning days in the 1960s and dissolved in 1989 after another third party had surged - the Parti Québécois. But to consolidate its gains, the PQ had to take power. It did that with a bang in 1976.
As for the Ralliement Créditiste, it never made it to the premier's office and had a tiny life span from 1970 to 1980.
Today, the attention turns to the ADQ. As was the case with René Lévesque and the PQ, The ADQ was born after a schism within the Liberal Party over the constitutional issue, leading to a different ideological approach on socio-economic issues as well.
Lévesque had chosen sovereignty-association and a more social-democratic vision. Dumont left the Liberals when Bourassa rejected the famous post-Meech Allaire report that asked for the patriation of 22 powers for Quebec. Dumont became more nationalist and moved to the right.
When the ADQ ended with 31 per cent of the vote at the 2007 election and stole the official opposition status from the PQ, the two-party notion was so strong that analysts began asking if the PQ wasn't the party that was now condemned to disappear.
But with support for the ADQ plummeting fast, the upward swing of the Liberals, and voters saying they find the PQ to be a more effective opposition than the ADQ, it's now the longevity of Dumont's party that's coming into question.
This decline is all the more problematic for Dumont because until the last election the ADQ was actually the only major party with steadily increasing support. In 1994, it got a tiny 6.5 per cent of the votes. In 1998, it was up to 12 per cent. It got 18 per cent in 2003, and finally surged to 31 per cent in 2007. The latest poll now puts it at 17 per cent.
And there's more worrisome data for the ADQ in the polls that show a whopping 14 per cent support for Québec Solidaire and the Green Party combined. Supposing that on election night, those numbers won't be as high, chances are that some of those voters will go to the PQ or vanish as abstentions.
The ADQ's downward trend in the polls now seems steady. But it did gain real support, slowly but surely, from 1994 to 2007.
Its 31 per cent in the last election might have been a lucky combination of circumstances for the ADQ. Dumont has tapped into a few ideas du jour, it's true, but the combination of a disastrous André Boisclair and a Jean Charest who was still unloved at the time was what really opened a window of opportunity for the ADQ. But that window has since been shut.
So the question returns: How much or how long can third parties survive here? If the ADQ finds a way again to tap into its real voting base - the one that kept growing since its creation - it just might prove that it is possible for a third party to hang in there longer than the other third parties that never made it to power.
Otherwise, it will simply join them in the history books.