It was too much to take. Too much for a second time.

As the cavernous room filled with ugly cries and chants, police radio pleas for help, images of a human herd driven by a crazed impulse to beat police, smash windows and storm the US Capitol, survivors of that day held hands and wept.

Several members of the House of Representatives, who were trapped on a balcony in the chamber as the attack unfolded on 6 January 2021, sat together at Thursday’s opening public hearing held by the select committee investigating the insurrection.

When a carefully crafted video of that day’s carnage was played, Congresswoman Pramila Jayapal watched haunted and spellbound and wiped a tear from her eye. When her colleague Cori Bush broke down, a tissue was passed along the line so she could wipe her eyes.

The pain of reliving it all was written on the faces of the group, who have provided emotional support to each other ever since. And the effect was magnified because of the stagecraft: the footage was shown on a giant cinema-style screen above the committee members’ head and the volume was turned up to a deliberately discomforting level.

Committee member Jamie Raskin had promised that the revelations would “blow the roof off the House”; this did at least ring in the ears and take root inside the head. Later Jayapal tweeted a single word: “Horrifying.”

In the hope of similarly cutting through to the American public, the hearing began at 8pm and was broadcast live on every major network except Fox News. Prime time is a language that Donald Trump, a former reality TV star, understands but this turned out to most closely resemble a courtroom drama. Think Law & Order comes to Washington.

There was an unlikely star prosecutor, Republican congresswoman Liz Cheney, who clinically and methodically laid out a damning case against Trump and those who still support the ex-president. There was gasp-inducing evidence pulled out of the hat, including video testimony from Trump’s daughter Ivanka.

There was a jury of millions watching at home: the court of public opinion. But missing, of course, was the accused himself. There was no case for the defence, no Trump in the dock sweating under the bright lights from two big chandeliers. His champions on Fox News and elsewhere will denounce it as a show trial. His critics will urge the attorney general, Merrick Garland, to bring a genuine criminal indictment.

The drama inside the drama here was Cheney versus Trump and a battle of wills over the direction of the Republican party. Poignantly the daughter of George W Bush’s vice-president, Dick Cheney, knows that the very act of prosecuting Trump might be an act of political self-immolation. The former president has backed a challenger to her in a Republican primary in Wyoming in August and rallied against her there two weeks ago.

“I keep waiting for Liz Cheney to flinch,” wrote Frank Bruni, a contributing opinion writer for the New York Times. “But no. She’s all in and she’s all steel. It could well be the political death of her. Or it could give her a kind of immortality more meaningful than any office.”

Cheney again refused to flinch on Thursday, arguing that Trump oversaw and coordinated a sophisticated seven-part plan to overturn the presidential election and prevent the transfer of power. He encouraged and endorsed the insurrection, refused to call off the mob and became angry with anyone who wanted to stop it, she alleged.

“And, aware of the rioters’ chants to ‘hang Mike Pence’, the president responded with this sentiment: ‘Maybe our supporters have the right idea.’ Mike Pence ‘deserves’ it.”

At that there was a murmur of disbelief from the members of Congress sitting at the back of the Cannon Caucus Room. Sitting beside chairman Bennie Thompson and other committee members on the dais, with five flags behind them, Cheney went on: “President Trump summoned the mob, assembled the mob and lit the flame of this attack.”

She introduced video clips that included William Barr, who was attorney general at the time of the election, testifying that he told Trump “in no uncertain terms” that he did not see evidence of voter fraud.

Another clip showed Trump’s daughter and senior adviser, Ivanka, in an unexciting grey room, responding to Barr’s assertion: “I respect Attorney General Barr so I accepted what he was saying.”

That will not have played well at Mar-a-Lago, the Trump redoubt in Florida. Betrayed by his own blood and kin! Now he must know how King Lear felt. “How sharper than a serpent’s tooth it is to have a thankless child.”

Almost as bad, Cheney also served up a clip of a speech by the once-devoted Pence, whom Trump pressured relentlessly to subvert democracy. The former vice-president stated baldly: “President Trump is wrong. I had no right to overturn the election. The presidency belongs to the American people and the American people alone. And frankly, there is no idea more un-American than the notion that any one person could choose the American president.”

The congresswoman added “What President Trump demanded that Mike Pence do wasn’t just wrong, it was illegal and it was unconstitutional.”

Cheney and fellow Republican Adam Kinzinger, who is not seeking re-election, have already been censured by the party for sitting on the committee and can expect more demonisation in the coming days. But she had a memorable rejoinder: “I say this to my Republican colleagues who are defending the indefensible: there will come a day when Donald Trump is gone, but your dishonor will remain.”

Eventually the case rested until the next hearing on Monday. The committee had delivered a mostly effective warning to America not to let Trump anywhere near the White House again.

But will America tune in for episode two? Civil rights activist and legal analyst Maya Wiley warned on Twitter: “We are getting an opening similar to a jury trial. You lay out what the jury will learn during the trial. In this case over several hearings. A jury is a captive audience. TV audience is not.”