But real life is not a (fake) movie, and Flake’s speech did not unite a thankful nation. Instead, many Trump critics were nonplused. Noting that Flake had voted with the president 91 percent of the time, the Democratic National Committee chairman, Tom Perez, said in a statement that his retirement “is symbol of a Republican Party whose leaders allow Donald Trump’s divisive politics to flourish as long as it serves their political interests, and who fail to criticize this dangerous president until it’s too late.” A headline on the progressive website ThinkProgress said, “Jeff Flake is not a hero, despite what he wants you to think.”

Well, I don’t know what Flake wants me to think, but I believe he behaved heroically on Tuesday. ThinkProgress sniped that it’s easy to criticize the president when your 18 percent approval rating precludes re-election. But while Flake has long had relatively low approval ratings, they really cratered precisely because of his opposition to Trump.

It’s certainly true that Flake has voted with Trump to advance right-wing policies, most of which I find morally repulsive. But Flake is extremely conservative — as of 2016, the American Conservative Union gave him a 93 percent lifetime rating, a score comparable to that of Jeff Sessions. The senator believed in the policies he was voting for; from his point of view, there was no valor in opposing them. All the same, he’s now arguing that telling the truth about Trump is more important than enacting his most cherished political priorities. In doing so, he’s sacrificed a career he’s spent a lifetime building. He’s given more than most to the fight against Trump and Trumpism.

Indeed, as much as I hate Flake’s politics, I suspect there’s a connection between his intense political commitments and his bravery. Not long ago, I spoke to Eyal Press, the author of “Beautiful Souls: The Courage and Conscience of Ordinary People in Extraordinary Times,” a book about those who resist immoral authorities and institutions. We tend, Press told me, to “think of these people as iconoclasts, or imagine that they are somehow people with a kind of oppositional spirit,” but in fact, most of them are true believers in the purported ideals of their organizations. It’s because they value those ideals so highly, he said, that they’re moved to break ranks when they see them tarnished.

To recognize the role of Flake’s conservative principles in fueling his dissent is not to absolve the conservative movement for Trump. For decades, Republicans have stoked the culture war to win the support of people hurt by their economic policies. Under the guise of pushing back against left-wing bias, the right has systematically tried to discredit all objective sources of information, ushering in a berserk reactionary postmodernism in which truth loses its meaning. And though the Republican Party’s racial appeals used to be more coded, it’s been capitalizing on white resentment for a long time.