Recently one of my daughters looked up from her iPhone to report that a young man from her high school had gone viral on social media. I figured perhaps he taught a labradoodle to operate a coffee maker and posted the video. To my surprise, she told me Christopher Justice was a Twitter sensation for a speech delivered during a classroom debate on the Confederate flag.

I remembered him from grade school, where he struck me as a shy boy with a lot on his mind. I clicked on the viral tweet, and there he was at 15, not shy at all. He cut a commanding figure as he disputed another student’s assertion that the Civil War was not about slavery. Holding a laptop and tapping the screen for emphasis, Justice dissected Article I, Section 9(4) of the Confederate constitution. Like most of that document, the passage borrowed verbatim from the U.S. Constitution — but added a clause that would protect slavery forever.

“If the Confederates really were fighting for states’ rights,” he asked, “then why is this the one thing they changed?”

His fame began when a YouTube algorithm steered a Houston teen to a video of the classroom debate, produced by student journalists at Shawnee Mission East High School in Kansas. The Houston tweeter, using the handle @chulopjm, posted Justice’s star turn on July 6, noting: “white boy pulled out the receipts.” Her post spread, and by Tuesday, the clip had been viewed more than 8 million times, liked by more than 300,000 people and shared by more than 100,000. Not bad for an analysis of the Confederate constitution.

When I followed the trail back to YouTube and launched the full 55-minute debate (as more than 360,000 people have done), I wasn’t surprised to find that the moderator was a social studies teacher named David Muhammad. An African American Muslim at a predominately white suburban school, “Mr. Mu,” as he’s known, is so charismatic (his side gigs are teaching karate and recording his own raps) that even kids who never took his class (mine, for example) count him among their favorite teachers.

Muhammad told me the debate was held in 2015, as governments across the South were removing Confederate symbols from official settings. The issue grew heated in all parts of the country, which was exactly why he felt it was ripe for a robust discussion at school.

“The classroom is the place to do that,” he said when I called. Too often, “we build climates like rallies and protests where the heat builds and builds, and then we expect people to have a civil debate.” His job, he believes, is to create chances for students to say what they think, and hear other points of view, in a way that is passionate but respectful.

Some 100 students crammed into Muhammad’s classroom as the teacher framed the goal of the exercise: “to facilitate a community where we can have an open discussion that’s civil.” The goal was not to win the debate; it was to hear and be heard.

The rollicking result was passionate, informed, often clever. Sometimes pleading, sometimes faltering, but never cruel. I agree with young Justice that slavery was the root of the Civil War, and, whatever the flag stood for in the 1860s, by the 1960s it was a symbol of white supremacy. But the counter-argument that the South seceded because of Northern tariffs was standard-issue history at places such as Harvard and Princeton for most of a century. I’m not surprised that some iconoclastic teenagers would still believe it in 2015.

The miracle of Twitter is that, like other social media, it makes possible the discovery and dissemination of worthy content from off the beaten track. It is the extreme democratization of news. Justice, now 18 and headed to college, expressed surprise, when I texted him, that a moment from the distant past — three years is an eon when you’re 18 — would suddenly return to such vibrant life.

But the irony is that Twitter itself has become the antithesis of Muhammad’s model classroom debate. As Maggie Haberman of the New York Times wrote recently, explaining her wise decision to step back from the platform: “The viciousness, toxic partisan anger, intellectual dishonesty, motive-questioning and sexism are at all-time highs . . . Twitter is not where a nuanced or thoughtful discussion can happen.” Twitter Chief Executive Jack Dorsey responded: “This is what we’d like to fix the most.”

Hurry, please. In the meantime, I draw hope from knowing that brave teachers in classrooms across the country are still modeling the virtues of civil debate. Today’s students, digital natives, may be less likely than their nonnative elders to be led astray by technology. If their parents and grandparents can resist the current urge to cleave the country, the kids will be alright.

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