Donald Trump wanted to install a loyalist as America’s top law enforcement official to overturn his election defeat but was thwarted by an internal revolt, an official investigation has found.

A 394-page report by the Senate judiciary committee’s Democratic majority offers the most detailed account yet of Trump’s last-gasp effort to pressure the justice department to destroy democracy.

“This moment was spine-tinglingly, chillingly close to shredding the constitution because Donald Trump tried to subvert, corrupt the constitution and the Department of Justice,” Senator Richard Blumenthal, a member of the committee, told reporters.

Trump declared himself, not Joe Biden, the true winner on election night in November 2020 and continued to pursue false claims of voter fraud despite a lack of evidence and repeated court defeats.

The interim Senate report describes how, at a White House meeting on the evening of 3 January, Trump considered ousting the acting attorney general, Jeffrey Rosen, and appointing the acting assistant attorney general, Jeffrey Clark, in his place.

The president told Rosen: “One thing we know is [that] you, Rosen, aren’t going to do anything to overturn the election.”

Clark was more open to pursuing Trump’s baseless allegations of fraud, and pushed Rosen and Donoghue to publicly announce that the justice department was investigating them. But several officials in the three-hour meeting told the president they would resign if he put Clark in charge at the department.

According to witnesses interviewed by the Senate committee’s majority staff, White House counsel Pat Cipollone cited a draft letter from Clark urging Georgia officials to convene a special legislative session on the election results as a “murder-suicide pact,” and Cipollone also threatened to quit.

Richard Donoghue, who was Rosen’s deputy at the time, replied that there was “no chance” he would sign the letter or “anything remotely like that”.

Donoghue told the committee that he warned Trump that all assistant attorneys general, and perhaps US attorneys and other senior department officials, would resign en masse if the president were to replace Rosen with Clark.

The preliminary Senate report also found that Trump held at least nine calls and meetings with Rosen or Donoghue or both, demanding to know why the justice department was not doing more to investigate his baseless claim of a stolen election.

And Mark Meadows, the White House chief of staff, asked Rosen to launch investigations based on at least four false election fraud claims, including a wild conspiracy theory known as “Italygate”, which held that the CIA and an Italian IT contractor used military satellites to manipulate voting machines and change Trump votes to Biden votes.

The judiciary committee intends to seek further witness interviews and records from the Trump administration. Its interim report is based on interviews with Rosen, Donoghue and Byung Jin Pak, former US attorney for the Northern District of Georgia, as well as hundreds of pages of calendars, emails and other documents.

Trump forced Pak’s resignation on 4 January because his investigation did not substantiate claims of fraud in Georgia. William Barr, who proved loyal to Trump on many issues, had stepped down as attorney general in December after refusing to back his groundless allegations.

The effort by Trump and his allies culminated in a deadly insurrection at the US Capitol on 6 January but ultimately failed and Biden took office on 20 January. However, the report raises concerns for future elections, suggesting that the democratic system relies in large part on the integrity of government workers and is therefore fragile. It calls for a clearer separation between the White House and justice department.

Democrat Sheldon Whitehouse, a senior member of the Senate judiciary committee, said on Thursday: “These findings show just how close Donald Trump and his lackeys came to crashing through the guardrails of our democracy.

“To boost Donald Trump’s election lies, Jeffrey Clark nearly cleared himself a path to control of the Justice Department where he could have done massive, lasting damage. Jeffrey Rosen and Richard Donoghue upheld the independence of the Department in the face of that barrage of pressure. But we might not have a Rosen and Donoghue next time around.”