Thanks Sean for your thoughtful analysis of potential coalition scenarios. I wonder, is it not possible that the Liberals and BQ could form government together without drawing the ire of the rest of Canada outside Quebec? If such a government were to give Quebec more-or-less whatever the BQ demanded, while also being free to govern the rest of the country as the Liberals see fit, could that not be a recipe for a minority government that could last longer than average? And regarding the pipeline, is it also not possible that in such a government the BQ might not object to the expansion of a pipeline between Alberta and BC, since it doesn't involve Quebec (and they really don't give a damn about the rest of the country)? I certainly can envision such a scenario playing out.
As a Quebecer, I don't see that happening (bearing in mind that I don't have a crystal ball, and all kinds of insane things have happened in politics here). It'd undermine each party's ideological base at a fundamental level.
For the last quarter-century, the Liberals have campaigned in Quebec on one basic line: "The Bloc's useless." Meanwhile, the Bloc campaigns on "Ottawa's hopeless". For the Liberals to give any kind of concessions the Bloc would find worthwhile, like a new constitutional accord, it'd require them to admit there was a legitimate reason for voting Bloc in the first place. A comparison might be made with the Conservatives allying with the Greens on a "stop pipelines" budget. There's ideological overlap in both of their coalitions, but there are some fundamental stumbling blocks there.
Also, for the Bloc to consent to forcing a pipeline through BC while ignoring the fact the same precedent would allow one to be forced through Quebec, it'd have to demonstrate the kind of ideological shortsightedness that I don't think it has. And what could the Liberals really promise in exchange? With a minority backed by the Bloc, they wouldn't have the legitimacy to push through a constitutional amendment even if it didn't require consent of provincial legislatures. At best, they could offer more money and a few tweaks like a single tax return. That's hardly the "beau risque" that'd justify putting a Bloc stamp of approval on Trudeau.
No, as counterintuitive as it seems, I can see the Bloc entering into an arrangement with either the Tories or the NDP – on different grounds – but not the Liberals. Both the Liberals and the Bloc would be writing off their own bases if they did so.
As I said the Conservatives are more likely - not becuase they are closer in positions but because they are big enough to not need their votes and abstentions would be enough. It is also possible that the Greens and NDP could even agree to the same pact in order to avoid a new election. an agreement that requires positive votes woudl be nearly impossible to create right now given the pipeline debate.
I anticipate that the most liekly result of the election - unless a party gets a majority - is some kind of nonaggression pact rather than a policy-based agreement to govern. Only the Conservatives and Liberals have the means at this point for that although other parties may be very pleased to see it happen...