The tight race in Rosemont for the October 5, 2026 Quebec general election stems from the riding's progressive voter base splitting between Québec solidaire candidate Gisèle Pouhe Njall and Parti Québécois nominee Pierre-Luc Brillant, following the departure of longtime independent MNA Vincent Marissal. Recent candidate nominations and early projections show these two leading with closely matched implied probabilities around 40-50 percent, while Liberal David Lavoie, CAQ's Nour Aliyah Attié, and Conservative Mildred Mathieu trail with lower support consistent with historical results. The absence of an incumbent, combined with provincial trends favoring PQ and QS competition in Montreal ridings, sustains the deadlock. Further separation could arise from local debates on housing and education, progressive voter turnout patterns, or campaign developments before the September 17 nomination deadline.