Rep. Justin Amash (R-Mich.), who advocates the impeachment of President Trump, held a rousing town hall in his home district last Tuesday.

He spoke about Trump’s many breaches of public trust. He described the constitutional obligation of Congress to check abuses of power by a president who has shamelessly violated his oath of office.

“I want to salute your courage,” said a self-identified Vietnam War veteran. At this, applause erupted in the hall. A standing ovation.

In photographs, the crowd looked largely white. Women could be seen in head coverings: Two wore Mennonite doilies, and at least one, Diane Luke, had on a red cap marked “Make America Great Again.” In a confrontation with Amash, she ended up stealing the show.

When Luke got her hands on the question mic, groans greeted her headgear. A big man stood and shouted. Nevertheless, she persisted.

“If you want to go along with the violating the public trust, how far does that go?” she asked Amash. Her syntax was faulty, but her point was clear: What about accountability for “the Democrats, who have done the same thing”? Then came the telltale earworms that mark American minds lost to reason: “deep state,” Hillary Clinton’s “silent coup.”

“Silent coup” is a favorite phrase of Mark Levin, a gonzo conspiracy theorist on Fox News. That wacko meme is further traceable to Russian propaganda from 2016 and a 1991 book, “Silent Coup,” that argued that President Nixon’s downfall was set up by Democrats trying to hide —you guessed it — a Democratic National Committee prostitution ring.

It was sorely tempting to tune out Luke while she waxed a tinfoil hat at the town hall. But she was worth listening to. In her halting way she eventually managed not just to get a point across, but to embody that point. In short, she was baffled. She was hoping right-wing folklore would get her out of her bafflement. But it only made her more baffled.

Luke put her confusion on display in the room, which took a measure of courage. For her to pick up political earworms right off the pop charts suggested a certain cognitive vulnerability.

This vulnerability is definitely not confined to town hall audience members. A prominent case is Attorney General William Barr, who echoes Fox News and Russian botnets when he alludes to “spying” by the Obama administration and Uranium One, a farrago that makes as much sense as leprechaun stories.

As Robert S. Mueller III reminded us last Wednesday, American democracy can be infected by scary ideas configured to rile us up. Some people fall so hard for crazy lies, according to former Trumpist troll David Weissman, they enlist in hostile foreign troll armies, repeating and spreading nutcase memes even when it costs them social ties, professional standing and their own sanity.

But others recover or resist. And at Amash’s town hall, Luke’s common sense, the best inoculation against propaganda, seemed to rally. In her telling, the deep state came down to “the bureaucrats.”

Suddenly, she was out of Fox News talking points and into her own lived experience.

“I don’t know if you’ve ever dealt with a bureaucrat, but it’s just mind-boggling that we have to deal with them,” she said. “I have a lot of experience.”

Bureaucrats. No kidding. Paperwork and red tape are the day-to-day manifestations of the frayed systems — in health care, banking, education, housing, the IRS —that bedevil us all. Think: rejected claims from insurance companies, brief enrollment windows, out-of-network charges, unintelligible “terms and conditions.” For any American without a coterie of personal lawyers and accountants, life routinely involves demoralizing roadblocks. Mind-boggling is right.

Amash didn’t address bureaucracy, which is too bad; it’s a kitchen-table issue. But he did model a brisk, energetic, focused way of sorting signal from noise with one’s full mental capacities. For an infuriated nation that often seems close to moral and intellectual disintegration, Amash’s commitment to keeping his mind unboggled is right on.

Luke had accused Amash of turning into a Democrat, in spite of the fact that his voting record is reactionary and straight-up Freedom Caucus. But, even if his votes reflect the worst of libertarianism, Amash at his town hall was an advertisement for thinking for yourself. He had studied the Mueller report and concluded the president had committed impeachable offenses. He was immune to being spoon-fed lies from outlets like Fox News.

Just as Luke had demonstrated bewilderment, Amash demonstrated the one way out of bewilderment: Ignore propaganda, inform yourself and speak up. This should be considered the square-one duty of citizenship. The fact that so many Republicans have shirked that duty is … mind-boggling.