Mr. Trudeau’s public image as a liberal feminist committed to gender equality also took a hit with the more recent affair involving the Montreal-based engineering firm SNC-Lavalin. The details of this evolving and very Canadian political scandal are difficult to explain. But in brief, it started with allegations that Mr. Trudeau’s office tried to interfere in then-Justice Minister Jody Wilson-Raybould’s investigation into the firm. The important part, for Mr. Trudeau’s brand, is that following the resignation of Ms. Wilson-Raybould and Jane Philpott, a former Treasury Board president, from Mr. Trudeau’s cabinet, the prime minister kicked them out of his party. For many, this was a shocking way to treat two of his most prominent female allies, including the country’s first Indigenous justice minister.

In Canada, these developments, as well as a host of others, have changed how liberals see Mr. Trudeau. He is far less popular than he was in 2015, a leader despised on the right and often ridiculed on the left.

These stories, though, rarely made a stir in the United States. Occasionally, I’d see articles alluding to Mr. Trudeau’s troubles. Recently, Hasan Minhaj’s Netflix series “Patriot Act” featured an episode with Mr. Trudeau, in which he uncomfortably answers questions about the gap between his image and his policies. But overall, the American story of Mr. Trudeau as a “dream politician for the left,” as Mr. Minhaj put it, stuck. Until now, that is.