I'll check in from my vacation for a couple of quick notes on the federal byelection results. (Though you'll also want to read IP's analysis if you haven't already.)
First, while the NDP's overwhelming byelection victory in Outremont is a huge story in its own right, the vote total involved signals that Mulcair may be able to hold the seat for a long time to come.
Remember that Jean Lapierre won the seat in 2006 with just over 14,000 votes, in a riding where over 40,000 voters went to the polls. Now, Mulcair holds the seat after winning over 11,000 votes with barely half the turnout. And with the NDP's standing obviously improving in Quebec and its voter list presumably far expanded from what it was a year ago, Mulcair should be a safe bet to be able to significantly exceed Lapierre's general election total - along with that of his competitors.
Second, as I'd speculated earlier, the results from the other two ridings may say even more about the Libs' lack of strength in Quebec (and the NDP's relative strength) than the Outremont vote total. While Outremont can be classified as being based on Thomas Mulcair's name rather than relative party strength, the NDP also showed enough party depth to beat out the Libs in Saint-Hyacinthe-Bagot. And even in Roberval-Lac-Saint-Jean, the Libs' star candidate - apparently backed by a number of dissident former Cons - wasn't able to break into double figures.
Now, as IP notes, the story here is at least as much about the strength of the parties which broke through rather than the weakness of the parties in free-fall. And while that's unfortunate in the case of the Cons' rise in Bloc territory, the NDP's successful Outremont push - and ability to push past the Libs in another riding which was a Bloc/Lib battle as recently as 2004 - offers a strong signal that the NDP is on the rise as a long-term choice for progressive Quebec voters.