How did it come to this? For five wretched hours, the vice-president of the United States found himself hiding in a barren underground garage with no windows or furniture. Somewhere above, a baying mob was calling for him to hang.

The story of the deadly insurrection on 6 January, when Donald Trump supporters stormed the US Capitol in an attempt to subvert democracy, has been told in newspapers, books and TV documentaries. But journalist Jonathan Karl has seen unpublished photographs from that day that tell a new story about Vice-President Mike Pence.

In his highly readable new book, Betrayal: The Final Act of the Trump Show, Karl recounts how the rioters broke into the Senate chamber, climbed up into the chair where Pence had just been presiding, posed for pictures and left him a chilling handwritten note: “It’s only a matter of time. Justice is coming.”

Congressional leaders Kevin McCarthy, Mitch McConnell, Nancy Pelosi and Chuck Schumer had been rushed to a secure location outside the Capitol. But Pence, who was resisting pressure from Trump and the mob to overturn the election result, a power he did not possess in any case, declined to follow.

“They wanted to take him out of the complex immediately and he refused to leave,” Karl says in an interview at an outdoor cafe in north-west Washington. “Pence is not a yeller but he yelled at his Secret Service lead agent, saying, ‘No, I’ve got a job to do, I am staying.’

“Then, as the crowd is coming in towards the Senate floor, they said we have to at least get out of here because the room he was in didn’t have anything secure.”

Surveillance video from the day shows Pence and his entourage being whisked down some stairs at a brisk pace. What happened next had been a mystery. Karl, who has reviewed all the pictures taken by the vice-president’s photographer, learned that the vice-president ended up in a loading dock beneath one of the Senate office buildings.

Karl, who is ABC News’s chief White House correspondent, says the images reveal Pence in a garage with concrete walls and concrete floor. The vice-presidential motorcade was there but Pence refused to get inside his vehicle, worried that they would drive away at the first sign of danger.

“Their first priority was to keep him safe. His priority was to stay. Those were not necessarily consistent. So for the first couple of hours at least, he refused to go inside the car.”

Pence “looks a bit distraught”, Karl recalls from the pictures. During these roughly five hours there was no communication with Trump, who was at the White House, watching the spectacle unfold on TV. But the commander-in-chief was telling the world what he thought of his deputy.

Karl continues: “There are a couple of shots where his chief of staff [Marc Short] is showing Vice-President Pence his phone and I was told that, in at least one of those shots, what is being shown is Trump’s tweet where he said, ‘Mike Pence didn’t have the courage.’

“Here he is, the one guy in leadership refusing to leave the complex, holed up in a concrete parking garage while people are chanting for his life upstairs. He’s being shown a tweet from the president, who has not bothered to call to see if he is safe, saying he didn’t have courage.”

There was another striking photo that day, after the insurrectionists had been chased out of the building so that Joe Biden’s election win could be certified. At around midnight, in statuary hall, Pence came face to face with Liz Cheney, a Republican congresswoman who would later vote for Trump’s impeachment.

“Liz Cheney says to him, thank you, you did the right thing, it was really important – something to that effect. And Pence just looks at her, no discernible expression, maybe also because he’s wearing a mask, and doesn’t really say anything. It’s as if he’s worried that he’ll be overheard saying something nice to Liz Cheney. But there’s a photo of that moment which would also be interesting to see.”

The pictures were taken by an official photographer whose salary is paid by taxpayers. Karl was denied permission to publish them but is confident they will be subpoenaed by the House of Representatives select committee investigating the events of 6 January.

Even when the dust had settled, Trump showed no remorse or compassion for Pence. In March, Karl raised the subject during an interview with the former president at his Mar-a-Lago estate in Florida. The conversation went as follows:

Karl: Were you worried about him during the siege? Were you worried about his safety?

Trump: No. I thought he was well protected. I had heard he was in good shape. No. Because I had heard he was in very good shape.

Karl: Because you heard those chants. That was terrible. I mean, you know, those –

Trump: Well, the people were very angry.

Karl: They were saying, ‘Hang Mike Pence!’

Trump: Because it’s common sense …

Karl adds now: “What he was doing was essentially justifying the chants of those that were calling for the murder of his own vice-president, and there wasn’t a second of a beat to say, ‘Now, that was outrageous, they may be angry, but we can’t –’ He didn’t say that. Not at all. It’s not present in his head.

“He’s still angry at Pence. He told me flatly that he would still be president if Pence did what he wanted to do and he didn’t know that he could ever forgive Pence.”

For four years, Pence had been Trump’s oleaginous lieutenant, defending his every move and keeping conservatives and Christian evangelicals on his side. But at the critical moment, with America teetering between democracy and autocracy, the vice-president and former Indiana governor chose democracy.

Karl explains: “I go into excruciating detail about the pressure that Pence was under. It was massive. It was relentless. It was public. It was private. It was from all directions and Pence, to his credit, was disloyal at exactly the right time. He was disloyal when it mattered the most. He had been loyal to Trump through everything else. He had enabled, you could argue, everything else and history will judge him for all of that.

“But at that moment, Pence did the right thing and it really mattered because I don’t know what would have happened. I asked a lot of people this and nobody can give me a good answer. I don’t think there is a good answer. He didn’t have the authority to overturn the election.

“He didn’t have the authority to throw out these electoral votes. But what if he did? It would have been chaos. What would Pelosi have done? How does it end? How do you get out of that? Eventually it wouldn’t have stood but how? The constitution’s not going to help you at that point. He’s basically stopping the last step in the certification of an election and that step is required for Biden to become president. So what if Pence just stopped it?”

The more he learned in researching the book, Karl writes, the more he became convinced that, as horrific as the events of 6 January were, America was far more imperilled than most people realised at the time. It was a miracle, he argues, that nothing more dire happened between Trump’s election defeat and Biden’s inauguration.

“The most important thing for people to take away from this book is an awareness that we came close to losing it all. Our democratic system has been around for well over 200 years but it’s actually fragile and more fragile than it has been at any point during our lifetimes.”

The system, no matter how ingenious its construction, ultimately relies on key individuals behaving honourably. Karl, whose previous book was Front Row at the Trump Show, continues: “There were many people along the way who, if they had done something else, the situation could have had a much worse and even more catastrophic end.

“The Michigan Republican leaders stand out to me because they were brought to the Oval Office, summoned there by Trump. They are leaders of a Republican party in a state where Republican voters are overwhelmingly entirely behind Donald Trump and they said, no, we cannot overturn our state’s election results.”

Another example was Chris Liddell, a White House deputy chief of staff who had served all four years. “This guy had a clandestine operation going on in the West Wing to aid the Biden transition because it’s required by law. But what if he didn’t? What if he broke that law? Who’’s going to come in?

“None of these people in their background would there be any indication that they would be the ones that would stand up against Donald Trump. But they did. Again, history will judge them for everything else they did but, in that moment, they helped this from becoming an even bigger crisis than it was.”

So it was that Trump did not have to be forcibly removed from the Oval Office or have his fingers prised from the Resolute desk one by one. Yet he continues to tower over the Republican party and hold grievance and vengeance-fuelled rallies. He is still pushing false conspiracy theories about a stolen election and attempting to recast the history of 6 January as a heroic stand by brave patriots.

Karl says: “It was clear from the interview that Donald Trump views January 6 as a great day and one of the greatest days of his presidency, which is amazing because it’s one of the darkest days in the history of the American republic.

“He, in his head, has convinced himself – and I believe he believes it – this was a tremendous day because all of these people came from all over the country to fight for him in a way that his own political allies had never been willing to fight for him. They wanted to ‘stop the steal’.”

Karl, 53, first met Trump in 1994 when he was a reporter at the New York Post and the property tycoon gave him a tour of Trump Tower, where newlyweds Michael Jackson and Lisa Marie Presley were staying. Trump hasn’t changed much, he finds, except in one important regard.

“The Trump I saw in 1994 was not as obviously angry and vindictive because the Trump in Mar-a-Lago has gained something and lost it, and is eager to deny that it was him who lost it and to blame others, including primarily those closest to him.”

Karl describes how, in a fit of pique after his defeat, Trump threatened to quit the Republican party and start his own but backed down after being warned that such a move would cost him millions of dollars. The author does not think Trump will run for the White House again in 2024 because of the risk of another humiliating loss.

If that prediction proves accurate and Trump’s name is not on the ballot, should we still be worried about the future of American democracy? “We have to be when you have a large segment of the population that doesn’t trust the results of an election, and the ground is being set to not trust the results of another election.

“The efforts that are being taken in the states where Republicans are in control to limit voting have also caused those on the other side of the political spectrum to believe that they can’t trust the results of a presidential election.”

Karl adds: “Our entire system is predicated on the idea that you fight it out in a campaign. Voters go and vote and the results are honoured. The winners are congratulated, the losers concede, and the fight goes on to the next election. Once you take that out of it, we’re in real trouble. So I am really worried. Trump is the great accelerant here but he’s not the original cause. It’s not just Trump.”