The collapse of Canada’s minor parties accounts for some of this volatility. The left-wing New Democratic Party fell from 18% of the vote to 6%. The right-wing People’s Party dropped from 5% to 1%. Yet changes in third-party votes are only faintly correlated to shifts in the margin between the big parties.

Pierre Poilievre’s Conservative Party saw pre-election polling momentum stall amid the trade war with the U.S. and Trump's "51st state" taunts.