Federal by-election · Quebec · expected

One man, one seat.

Alexandre Boulerice was the last New Democrat in Quebec, and very nearly the last New Democrat vote: 40.5% here against 4.5% province-wide. He is leaving to run for Québec solidaire. The question is how much of that vote was ever his party’s.

Seat vacant · writ not yet issued

The Vote-Scope forecast

Projected vote share (10th–90th percentile, median marked)

Liberal

37.5 % Chance of winning: 97 %

Bloc Québécois

23.7 % Chance of winning: 1.5 %

NDP

23.1 % Chance of winning: 1.1 %

Conservative

10.3 % Chance of winning: < 1 %

Green

5.1 % Chance of winning: < 1 %

The personal-vote correction here is capped at 18 points — under half of Boulerice’s own 2025 vote, because an effect larger than half stops being a personal vote and becomes the whole seat attributed to one person — and floored at 19%, so the local progressive base survives his departure. Orphaned votes are transferred on ideological lines rather than in proportion to each party’s local strength, which would have handed the Conservatives votes they were never going to receive.

How this projection is built

Personal vote removed

18 points stripped from the NDP baseline — the share that belonged to Alexandre Boulerice rather than to the party.

42.9 % → 24.9 % · floor 19 %

2025 result — the seat as it was won

NDP 40.5 %

Liberal 31.2 %

Bloc Québécois 18.1 %

Conservative 6.8 %

Green 2.3 %

72.3 %

Why this by-election exists

Boulerice has sat as an independent since April 27, 2026 and will run for Québec solidaire in Gouin at the Quebec general election.
The naive comparison — 40.5% here against 4.5% for the NDP across Quebec — overstates the personal effect, because it lumps central Montreal in with the regions.
The right control group is the neighbouring, comparable ridings, which gave the NDP 18.6% (Laurier—Sainte-Marie), 16.1% (Papineau) and 12.8% (Hochelaga—Rosemont-Est) with no star on the ballot.
The local progressive base is real: Québec solidaire won all four overlapping provincial ridings in 2022, including Gouin at 59.4% — its strongest seat in Quebec. That vote does not transfer to the NDP one-for-one, but it rules out collapsing them to the provincial average.
Left uncorrected, the general-election model still carries the NDP near 44% here — the personal vote of a candidate who is not running.

No polling day yet

Under the Canada Elections Act the writ must issue between 11 and 180 days after the Speaker notifies the Chief Electoral Officer of the vacancy.

Sources