The surest evidence of Trump’s dominance is on the campaign trail. As The Times’s Jonathan Martin reported, many Republicans, including Ted Cruz, are making the argument that if Democrats take over Congress, they will impeach the president. In other words, far from ignoring Trump, these Republicans are making defending him the center of their campaigns.

In red states, as Josh Kraushaar of the National Journal noted, Republicans compete to see who is the most Trumpish. In Indiana, the men vying for the Republican Senate nomination underline their support for the trade war. One candidate has a slogan, “Defeat the elite,” while another promises to “Make America Great.”

Even in blue states, Republicans refuse to criticize the man. In districts across Southern California, 11 Republican House candidates were asked about their positions on various issues. Seven of them refused to answer any question concerning Trump, and the four who did were strongly supportive.

Democratic anti-Trumpers had better hope they win in 2020, because their attacks have only served to entrench Trumpism on the right. Meanwhile, if Republican never-Trumpers were an army, they’d be freezing their buns off in Valley Forge tweeting over and over again that these are the times that try men’s souls.

Why has Trump dominated? Part of it is tribalism. In any tribal war people tend to bury individual concerns and rally to their leader and the party line. As late as 2015, Republican voters overwhelmingly supported free trade. Now they overwhelmingly oppose it. The shift didn’t happen because of some mass reappraisal of the evidence; it’s just that tribal orthodoxy shifted and everyone followed.

Part of the problem is that anti-Trumpism has a tendency to be insufferably condescending. For example, my colleague Thomas B. Edsall beautifully summarized the recent academic analyses of what personality traits supposedly determine Trump support.

Trump opponents, the academics say, are open-minded and value independence and novelty. Trump supporters, they continue, are closed-minded, change-averse and desperate for security.