Here is my interpretation of last night’s by-election results by party.
Liberals: It was definitely a good night for the Liberals. While they lost a bit of ground in Sturgeon River-Parkland, they have never done particularly well in this riding. They did however pick up Lac Saint Jean which is in the heart of what used to be separatist territory. The last time this riding elected a Liberal MP was 1980 when the party won 74 of the 75 seats in the province so after a tough few weeks this will be a huge morale booster for much of the Liberal caucus. The Liberals only have to have a net loss of 15 seats to lose their majority and lose 43 seats to the Tories to lose outright, so with it being an uphill battle to keep losses in English Canada to under 15 seats, the Liberals need to gain elsewhere to offset these. With these results, the Liberals could win as many as 60-65 seats in Quebec which would be enough that they could afford to lose up to 40 seats in English Canada before losing their majority, so definitely is good news for them for now. But Quebec can change quickly so the strong Liberal support there is not guaranteed to last through to October 2019.
Conservatives: A disappointment but not a disastrous night. They easily won Sturgeon River-Parkland as expected and increased their vote share by 7%. If they were to see a similar swing in British Columbia and Ontario, this could result in them picking up many seats, but at the end of the day seats not votes matter, so running up the margins in safe ridings does little on its own. On the other hand the loss of Lac Saint Jean was a disappointment although this was more of a Denis Lebel riding than Tory one. Of the 12 Tory ridings in Quebec, all of them except Lac Saint Jean were in the Quebec City region suggesting to me it was Denis Lebel, not the Tories who won the riding in 2015. Further more, in the adjacent ridings of Jonquiere and Chicoutimi-Le Fjord, the Tories got under 20% last federal election, so coming in second and getting 25% of the popular vote is not a horrible showing. It is better than what the party did in 1997, well above the combined vote of the two legacy parties in 2000, and almost five times what it was in 2004. So at least the party has a strong foundation they just need to build on it. Still, Scheer needs to pick up his game in Quebec if he wants to have any chance of winning in 2019. My advice would be to make Gerald Detell his Quebec deputy and put him in charge of building up the infrastructure to win seats in Quebec and also developing a Quebec specific platform.
NDP: If it was a disappointment for the Tories, it was definitely a bad night for the NDP. They failed to get their deposit back in Sturgeon River-Parkland, which while not surprising, its important to note all provincial ridings within its boundaries voted NDP in the last provincial election. They also came in fourth and barely got back their deposit in Lac Saint Jean so they have to stop their bleeding of votes in Quebec if they want to see any improvement in 2019. The only positive is the NDP still outperformed what they did in 2004, 2006, and 2008. That being said I figured with Jagmeet Singh, the party still can win seats in Quebec, but will probably be on the Island of Montreal, not the regions of Quebec. So the Outremont by-election once Mulcair gives up his seat will be the real test for them.
Bloc Quebecois: Lac Saint Jean voted 2/3 in favour of separation in the 1995 referendum and was Lucien Bouchard’s old riding, so if there was going to be any BQ revival it would be here and they failed. Polls have been all over the place in respect to the BQ with some showing them recovering, others still in the tank. The by-election results seem to suggest the latter is probably the case.
Looking ahead though, I think the by-elections in South Surrey-White Rock and Scarborough-Agincourt will be telling. Both are suburban ridings which are key to whomever wins in 2019. A Liberal gain in South Surrey-White Rock and strong win in Scarborough-Agincourt would signal the Liberals are still strong across Canada. On the other hand a Tory hold in South Surrey-White Rock and pick-up in Scarborough-Agincourt or at least a strong second would show the Tories are once again competitive in suburban English Canada meaning Quebec is where their main focus will have to be to get the additional seats needed to win in 2019.