Interesting article by Eric Grenier on Trudeau's midterm slump
http://www.cbc.ca/news/politics/grenier-midmandate-polls-1.4597222 . Looking at the past it seems he could certainly recover, but also just as easily slide further. Usually parties recover by changing channels so probably needs to focus more on economic issues and less virtue signaling and maybe be in front of the camera a little less. At the same time if Ford wins in Ontario that should help him there as Quebec and Atlantic Canada will likely go Liberal no matter what in most seats, BC will be a mix of the three parties, Prairies mostly Tory, so comes down to Ontario where unpopularity of Wynne is probably dragging him down. Looking at past first term provincial governments, at this point, this is what I've found.
BC:
NDP in the 90s: Trailing by over 25 points, but did manage to come back and win in 1996 although this was before fixed election dates so had an extra year and also change of leader.
BC Liberals 2004: I think 18 months out the BC Liberals were around 45% so close to what they got in 2005, but NDP was much lower than the 42% they got due to vote splits. However, 12 months out, the NDP had pulled ahead and wasn't until the final four months the BC Liberals regained the lead.
SK:
NDP in 90s: Believe Romanow had a big lead at this point, but not sure if he went up or down.
Saskatchewan Party circa 2010: Brad Wall was polling north of 60% so similar to the results in 2011.
MB:
NDP circa 2002: NDP was in the lead but I believe polls showed things tighter than they actually were in 2003 so NDP gained.
ON:
Libs circa 1988: David Peterson had massive lead, but lost in 1990 on opportunistic early election call
NDP circa 1993: Trailing very badly in the polls, I believe below what they got in 1995, mind you Liberals not PCs were in the lead.
PCs circa 1998: I believe polls were tied or Liberals slightly ahead but in the final year PCs regained the lead and won in 1999.
Liberals circa 2006: Liberals tied or slightly ahead but in minority territory so did better in 2007 that polls at this point.
Actually in Ontario, since 1995, the governing party has always rebounded somewhat and the opposition in each case dropped a bit.
QC:
PLQ circa 2006: Charest trailing in the polls although starting to recover a bit. I think the PLQ actually got roughly the same percentage as polls said in 2007, the big differnece is PQ plummeted while ADQ surged.
NB:
PCs circa 2002: PCs led by Bernard Lord had a massive lead in the polls while in 2003 they barely hung onto power
Liberals circa 2009: Liberals ahead in the polls, but plummeted after the Hydro-Quebec deal and ended up losing quite badly in 2010
PCs circa 2013: Were trailing by 20 points so recovered a bit but not enough to win in 2014.
PEI:
Liberals circa 2010: Had a 20 point lead so tightened although I think Liberal support only dropped a few points, but PCs surged by 10 points while third parties fell. Liberals still won handidly in 2011 anyways.
NS:
NDP Circa 2012: Trailing badly in the polls but did even worse on election day. Liberal support was pretty much bang on what they got but PCs climbed and NDP fell further.
Liberals circa 2016: Liberals had a 25 point + lead yet narrowed to only 3.5 points in 2017 election.
NL:
PCs circa 2006: PCs had big lead then, but grew even larger in 2007
So as you can see certainly Trudeau can eaisly recover to majority territory, but also the Tories (I don't think they are likely to get a majority BTW) could also climb into majority territory too based on history. Ironically enough since the 80s, the Tories in every election save 1993 have always outperformed what polls showed them 18 months earlier even in the elections they lost. For the Liberals they have underperformed their polls 18 months in every election save 2015 when they outperformed them (NDP underperformed there).
Poll
