Six months since the House committee investigating the Jan. 6, 2021, assault on the Capitol completed its work, a far-right ecosystem of true believers has embraced “J6” as the animating force of their lives.

They attend the criminal trials of the more prominent rioters charged in the attack. They gather to pray and sing “The Star-Spangled Banner” on the outer perimeter of the District of Columbia jail, where some two dozen defendants are held. Last week, dozens showed up at an unofficial House hearing convened by a handful of Republican lawmakers to challenge “the fake narrative that an insurrection had occurred on Jan. 6,” as set forth by Jeffrey Clark, a witness at the hearing and a former Justice Department official who worked to undo the results of the 2020 election.

The 90-minute event was a through-the-looking-glass alternative to the damning case against former President Donald J. Trump presented last year by the Jan. 6 committee. In the version advanced by five House Republicans who attended the hearing — Matt Gaetz, Paul Gosar, Ralph Norman, Marjorie Taylor Greene and Troy Nehls — as well as conservative lawyers and Capitol riot defendants, Jan. 6 was an elaborate setup to entrap peaceful Trump supporters, followed by a continuing Biden administration campaign to imprison and torment innocent conservatives.

Writ large, their loudest-in-the-room tale of persecution rather than prosecution might be dismissed as fringe nonsense had it not migrated so swiftly to the heart of presidential politics. Mr. Trump has pledged to pardon some of the Jan. 6 defendants if he returns to the White House, and his chief challenger for the 2024 Republican nomination, Gov. Ron DeSantis of Florida, has signaled he may do the same.

More than half, or 58 percent, of self-described conservatives say that Jan. 6 was an act of “legitimate political discourse” rather than a “violent insurrection,” according to a poll three months ago by The Economist/YouGov.

The counternarrative is in part animated by a series of particularly stiff sentences for the Jan. 6 defendants, including one of more than 12 years in prison handed down on Wednesday for a rioter who savagely assaulted a D.C. police officer, Michael Fanone.

The audience for the hearing in the Capitol Visitor Center included several of the most avid and successful promoters of the Jan. 6 counternarrative.

Among them were Micki Witthoeft, the mother of Ashli Babbitt, the Air Force veteran and QAnon adherent who was fatally shot by a Capitol police officer during the riot and is now heralded as a martyr by the far right; Nicole Reffitt, whose husband, Guy Reffitt, was sentenced to more than seven years in prison for his role in the riot and who now helps organize nightly vigils at the D.C. jail; Tayler Hansen, who has claimed to possess videotaped evidence of antifa elements instigating the violence at the Capitol, but who did not respond to a request from The New York Times to view the footage; and Tommy Tatum of Mississippi, who describes himself as an independent journalist and has inferred from various unidentified characters who appear in his own footage that sophisticated teams of plainclothes federal agents orchestrated the breach of the Capitol.

The Jan. 6 deniers range from true believers to flighty opportunists, with fevered arguments among them as to who is which. Mr. Tatum and William Shipley, a lawyer who has represented more than 30 Jan. 6 defendants, have for example accused each other on Twitter of cynical profiteering.

One generally admired within the group is Julie Kelly, a former Illinois Republican political consultant, cooking class teacher and pandemic lockdown critic who writes for the conservative website American Greatness. Ms. Kelly has asserted that the Biden administration is “on a destructive crusade to exact revenge against supporters of Donald Trump” and has accused Mr. Fanone, who was beaten unconscious by the rioters at the Capitol, of being a “crisis actor.” She was a frequent guest on Tucker Carlson’s prime-time show before Fox fired him in April.

Last month, aides to Speaker Kevin McCarthy gave Ms. Kelly and two other conservative writers, John Solomon of Just the News and Joseph M. Hanneman of The Epoch Times, permission to ferret through the Capitol’s voluminous Jan. 6 security footage, the only journalists other than Mr. Carlson to obtain such access.

In an interview the day before the House hearing, Ms. Kelly said she was scouring the video in hopes of learning the provenance of the infamous gallows that were seen on the Capitol grounds on Jan. 6. “Did Trump supporters go there and build that? I doubt it,” she said. Ms. Kelly also hopes to learn whether nefarious “agitators” were already inside the Capitol before the breach. She variously termed Jan. 6 “an inside job” and a “fed-surrection.”

Ms. Kelly recounted a meeting she and a fellow supporter of Jan. 6 defendants, Cynthia Hughes, had last September with Mr. Trump at his golf club in Bedminster, N.J. She said she told the former president that the defendants felt abandoned by him: “They’re saying to me: ‘We were there for him. Why isn’t he here for us?’” Ms. Hughes informed Mr. Trump that the federal judges he appointed were “among the worst” when it came to the treatment of the riot defendants.

Surprised, Mr. Trump replied, “Well, I got recommendations from the Federalist Society.” Ms. Kelly said he then asked, “What do you want me to do?” She replied that he could donate to Ms. Hughes’s organization, the Patriot Freedom Project, which offers financial support to the defendants. Mr. Trump’s Save America PAC subsequently gave $10,000 to the group.

Others in the ecosystem contend that Mr. Trump’s contribution to the cause is manifest by the slings and arrows he has himself suffered since that day. “I call him Jan. Sixth-er Number One,” said Joseph D. McBride, perhaps the most visible of the lawyers representing the defendants. “He’s under the gun. He’s being investigated and indicted.”

Mr. McBride’s clients include Richard Barnett, who posed for a photograph with his foot on Speaker Nancy Pelosi’s desk, as well as Ryan Nichols, who exhorted fellow protesters to target elected officials, yelling, “Cut their heads off!”

Mr. McBride also represented two Stop the Steal rally organizers subpoenaed by the Jan. 6 committee, Ali Alexander and Alex Bruesewitz. It was Mr. Bruesewitz who introduced Mr. McBride to Donald Trump Jr., which led to several invitations to Mar-a-Lago, Mr. Trump’s club in Palm Beach, Fla.

“I’ve lost count at this point,” Mr. McBride said, adding that the club “is a good place to network.”

Mr. McBride was also a frequent guest on Mr. Carlson’s show, including the time he claimed that a mysterious man seen at the Capitol on Jan. 6 with his face obscured in red paint was “clearly a law enforcement officer.” Shown evidence later that week by a HuffPost reporter that the man was a well-known habitué of St. Louis Cardinals baseball games, Mr. McBride replied: “If I’m wrong, so be it, bro. I don’t care.”

He did acknowledge a certain dubiousness to the claim that the mostly white male conservatives who showed up at the Capitol on Jan. 6 had the judicial deck stacked against them.

“Pre-Jan. 6, anytime you heard the term ‘two-tier system of justice,’ it’s Blacks, it’s Latinos, it’s the infringed, it’s the poor, it’s the drug addicted, it’s the marginalized, it’s the L.G.B.T.Q. community,” he said. That coalition of victims, Mr. McBride insisted, now included the MAGA supporters he represented.

Insha Rahman, the vice president for advocacy and partnerships at the Vera Institute of Justice, a nonprofit focused on criminal justice reform, agrees, up to a point. Mr. McBride and the others are raising “unfortunately a fact of life for over two million Americans who are behind bars,” said Ms. Rahman, who has visited the D.C. jail several times and concurs that its conditions are inhumane, though no worse, she said, than detention facilities in Chicago, Los Angeles and Houston.

Still, she said, the privileges afforded the Jan. 6 pretrial detainees in their particular wing — individual cells, a library, contact visits, the ability to participate in podcasts — “are not at all typical.”

“But I don’t want to call that special treatment,” Ms. Rahman said. “That’s the floor for what every incarcerated person in America should have a right to expect.”

For now, the protagonists of the alternative Jan. 6 narrative are not particularly focused on prison reform. Nor are they willing to give up.

As Mr. McBride said: “Do I think we’ll ever get to the bottom of it? We still haven’t solved the J.F.K. assassination.”