Hours after the deadly Capitol attack on 6 January 2021, the Senate Republican leader, Mitch McConnell, told a reporter he was “exhilarated” because he thought Donald Trump had finally lost his grip on the party.

Close to a year and a half later, however, with midterm elections looming, Trump retains control over the GOP and is set to be its presidential candidate in 2024.

What’s more, McConnell has said he will support Trump if so.

McConnell’s short-lived glee over Trump’s apparent downfall is described in This Will Not Pass, an explosive new book by Jonathan Martin and Alexander Burns of the New York Times which will be published next week. The Guardian obtained a copy.

The two authors describe a meeting between one of them and McConnell at the Capitol early on 7 January 2021. The day before, a mob Trump told to “fight like hell” in service of his lie about electoral fraud attempted to stop certification of Joe Biden’s election victory by forcing its way into the Capitol.

A bipartisan Senate committee connected seven deaths to the attack. In the aftermath, 147 Republicans in the House and Senate nonetheless lodged objections to electoral results.

According to Martin and Burns, McConnell told staffers Trump was a “despicable human being” he would now fight politically. Then, on his way out of the Capitol, the authors say, McConnell met one of them and “made clear he wanted a word”.

“What do you hear about the 25th amendment?” they say McConnell asked, “eager for intelligence about whether his fellow Republicans were discussing removing Trump from office” via the constitutional process for removing a president incapable of the office.

Burns and Martin say McConnell “seemed almost buoyant”, telling them Trump was now “pretty thoroughly discredited”.

“He put a gun to his head and pulled the trigger,” McConnell is quoted as saying. “Couldn’t have happened at a better time.”

The authors say McConnell indicated he believed he would regain control of his party, alluding to a previous confrontation with the far right and saying: “We crushed the sons of bitches and that’s what we’re going to do in the primary in ’22.”

McConnell also said: “I feel exhilarated by the fact that [Trump] finally, totally discredited himself.”

McConnell’s words ring hollow, in fact, as the 2022 midterms approach. Trump endorsements are highly prized and Republicans who voted for impeachment are either retiring or facing Trump-backed challengers.

Trump was impeached for a second time over the Capitol attack but as Burns and Martin describe, McConnell swiftly realised that most Republican voters still supported the former president – many believing his lie about electoral fraud – and that most Republicans in Congress were going to stay in line.

Burns and Martin describe how in Trump’s Senate trial, Democratic House managers sought to convince McConnell of their case, knowing his loathing for Trump and hoping he would bring enough Republicans with him to convict.

But McConnell, grasping a legal argument that said Congress could not impeach a former president, did not join the seven Republicans who did find Trump guilty of inciting an insurrection.

After voting to acquit, McConnell excoriated Trump, saying he was “practically and morally responsible” for the Capitol attack.

That did not change the fact that thanks in large part to McConnell, Trump remains free to run for office again.