She said Obama and senior officials in his administration had “[laid] the groundwork for … a years-long coup” against Trump after his victory over Hillary Clinton by “manufacturing intelligence” to suggest that Russia had tried to influence the election. That included using a dossier prepared by a British intelligence analyst, Christopher Steele, that they knew to be unreliable, Gabbard claimed.

The post-election intelligence estimates contrasted with findings reached before the election, which indicated that Russia probably was not trying to interfere.

In extraordinary comments calling for prosecutions, she added: “The information we are releasing today clearly shows there was a treasonous conspiracy in 2016 committed by officials at the highest level of our government.

“Their goal was to subvert the will of the American people and enact what was essentially a years-long coup with the objective of trying to usurp the President from fulfilling the mandate bestowed upon him by the American people.”

“No matter how powerful, every person involved in this conspiracy must be investigated and prosecuted to the fullest extent of the law, to ensure nothing like this ever happens again. The American people’s faith and trust in our democratic republic and therefore the future of our nation depends on it,” she continued.

Gabbard, a former Democratic member of Congress, said she was passing documents supporting her case to the justice department. They included a partially redacted intelligence community assessment from the Obama administration on cyber threats to the 2016 election and a series of previously classified memos, including some from the office of James Clapper, who served as Obama’s director of national intelligence.

Clapper is one of several officials named by Gabbard as apparently implicated in the supposed conspiracy. Others include John Brennan, the former CIA director, John Kerry, the then secretary of state, Susan Rice, the national security adviser at the time, Andrew McCabe, the then deputy FBI director, who later fell foul of Trump, and Obama himself.

The attempt to return the spotlight back to the Russia investigation – long derided by Trump as a “hoax” – comes as the US president finds himself in the maelstrom of the lingering scandal over the disgraced financier Jeffrey Epstein, who was found dead in his prison cell in 2019 while awaiting prosecution on sex-trafficking charges.

The Trump administration has come under mounting pressure from the president’s make America great again (Maga) base to release files on the case, including a supposed list of Epstein’s influential clients.

Trump, in response, has variously dismissed the existence of such files or said they were invented by Obama and members of his administration, including James Comey, the former FBI director, and Joe Biden, vice-president in the Obama administration.

Commentary accompanying a series of Obama-era memos published by Gabbard’s office uses terms characteristic of Trump and his most ardent supporters to paint an alleged conspiracy to discredit his 2016 win.

Following a meeting on 9 December 2016 of Obama’s most senior national security team, the document – entitled the Russia Hoax – says: “Deep State officials in the IC [intelligence community] begin leaking blatantly false intelligence to the Washington Post … claiming that Russia used “cyber means” to influence “the outcome of the election.

“Later that evening, another leak to the Washington Post falsely alleges that the CIA “concluded in a secret assessment that Russia intervened” in the election to help President Trump.”

On 6 January the following year, the document continues: “The Obama administration shares the unclassified ICA [intelligence community assessment] with the public. It falsely alleges, based in part on ‘further information’ that had ‘come to light’ since the election, that Putin directed an effort to help President Trump defeat Hillary Clinton. This ‘further information’ is later confirmed to be the Steele dossier.”

The assessment “suppressed” previous pre-election assessments that Russia lacked the intent or means to successfully hack the poll, Gabbard’s report alleges.

The Steele dossier, which contained salacious details of “kompromat” allegedly held by Russian intelligence on Trump, formed part of the basis for a lengthy investigation conducted by Robert Mueller, who was appointed as special counsel into the Russia affair. Mueller’s subsequent report concluded that Russia interfered “in sweeping and systematic fashion” in the election campaign but “did not establish that members of the Trump campaign conspired or coordinated” with the Russian government’s activities.

Gabbard’s nomination as national intelligence director was one of Trump’s most contentious. It drew criticism because of her lack of previous intelligence experience, having never even served on a congressional committee on the subject, and a track record of supportive comments about Russia’s President Vladimir Putin and repeating Kremlin talking points on the war with Ukraine.