OTTAWA — When Canadians decide this fall whether to return Prime Minister Justin Trudeau to office, Quebec’s votes will be critical.

So it’s a good thing for Mr. Trudeau that many in the province have stood by him this year even as his former justice minister accused him of bullying her over her handling of a criminal bribery case. On Wednesday, the country’s ethics commissioner found that the prime minister’s behavior violated the ethics law.

The reason Quebecers have been so loyal is that the case involved a major Quebec-based engineering company, SNC-Lavalin, which is a household name in the province, a source of pride, and a symbol of success.

Mr. Trudeau wanted the company to pay a fine, not face a criminal conviction. And he has steadfastly maintained that he was only trying to save jobs in Canada because a criminal conviction would bar the company from government work.