There’s an asymmetry in our politics that I find increasingly frustrating. I’m perfectly happy to condemn bigotry, extremism, and conspiratorial garbage when it comes from the right. I do it all the time. And I’m quite happy that three of the most prominent traffickers in such bile—Tucker Carlson, Marjorie Taylor Greene, and Thomas Massie—have been repudiated by the president and excised from the GOP. But when similarly ugly behavior emerges on the left, getting Democrats to offer the same unequivocal condemnation can feel like pulling teeth. Part of the problem is that the mainstream left has failed to articulate an affirmative political vision that extends beyond opposition to Trump—or to draw clear lines against its own extremes. The result has been a sustained trend of ceding ground within the party to radical socialists and figures who have expressed sympathy for Islamist terrorists.