While Justin Trudeau's poll numbers have sunk amid the controversy, Andrew Scheer and Jagmeet Singh have not seen a boost to their own polling numbers as opposition leaders. But it's still early days, say strategists.

Left to right, Conservative Leader Andrew Scheer, Prime Minister Justin Trudeau, and NDP Leader Jagmeet Singh. Mr. Trudeau's polling numbers have taken a hit in the wake of the SNC-Lavalin story. Mr. Scheer shouldn’t have called for Mr. Trudeau’s head so early in the game, says ex-Conservative adviser Tim Powers, while pollster Frank Graves says Mr. Singh could benefit from focusing on the corporate accountability aspects of the SNC-Lavalin affair.