Weeks after the 2020 election, Donald Trump reviewed a draft executive order that authorized the national guard to seize voting machines and verbally agreed to appoint Sidney Powell, a campaign lawyer and conspiracy theorist, as special counsel to investigate election fraud.

The two previously unreported actions of the former president – which is certain to interest the House select committee investigating the Capitol attack and Trump’s efforts to overturn his defeat – came during a contentious White House meeting on 18 December 2020.

Trump never followed through with issuing a formal executive order authorizing the seizure of voting machines or appointing a special counsel. But four sources with detailed knowledge of what transpired during the 18 December meeting described to the Guardian how close he came to doing so.

The draft executive order Trump reviewed was one of the final versions Powell had prepared. An early version of the document was published by Politico. Another version, obtained by CNN, empowered the Department of Homeland Security instead of the Department of Defense.

But all versions included language that would have allowed Trump to appoint a special counsel to investigate claims of foreign interference in the 2020 election, which the Department of Justice had already determined were without foundation.

The draft executive order seen by Trump was retained automatically by the White House as a presidential record. It was recently turned over to the select committee by the National Archives after the supreme court rejected Trump’s appeal to block its release.

Trump was handed the document when he sat down with four informal advisers – Powell, Trump’s former national security advisor Michael Flynn, former Trump aide Emily Newman and former Overstock chief executive Patrick Byrne – who had arrived at the White House unannounced.

The group had not scheduled an audience with Trump, but after Byrne messaged an acquaintance, they were cleared to enter the White House by Garrett Ziegler, a policy aide to former Trump advisor Peter Navarro, and Patrick Weaver, an aide with the National Security Council.

It is understood that the four were not registered in the West Wing guest access system as meeting with the former president, which may have violated national security protocols.

In a statement, Byrne said Trump had called the group into the Oval Office after he saw Flynn, his former national security adviser, with the rest of the group about 25ft from the room. Eric Herschmann, a White House senior adviser, slipped in behind them.

Trump first reviewed the draft executive order and documents brought by Powell, including a physical copy of Trump’s executive order 13848 that authorized sweeping powers in the event of foreign election interference, as she ran through the supposed legality of suspending normal law.

Powell and Newman told Trump that he could rely on that order and classified National Security Presidential Memoranda 13 and 21 – cyber-security memos referenced in Powell’s draft executive order – to have the national guard seize voting machines.

That prompted pushback from the former White House counsel Patrick Cipollone, who had joined the meeting with former White House staff secretary, Derek Lyons, who supported Cipollone’s claim that Trump lacked the constitutional authority to take such measures.

Byrne made another attempt to convince Trump to appoint Powell as special counsel and have Flynn act as “field marshal” to coordinate her efforts. The draft executive order said Flynn would be “direct liaison” to coordinate the “applicable US departments and agencies”.

Byrne claimed Trump had a range of options. He could decide whether to investigate election fraud in six, 12 or 31 states; whether to “image” hard drives in voting machines or seize them; and whether to have that done by the national guard, DHS or the FBI.

Trump appeared open to such advice. Late that Friday night, two of the sources said, he told Cipollone he would just make Powell special counsel. When Cipollone said Powell would need a security clearance, which he said was probably impossible, Trump said he would grant it.

But after nearly all of Trump’s formal advisers shot down Powell’s suggestions, Trump did not sign the draft executive order. Instead, he instructed Powell to coordinate with his attorney, Rudy Giuliani, about seizing voting machines or appointing a special counsel.

That posed a problem for Powell, who had been ejected from the Trump campaign’s legal team a few weeks beforehand at Giulaini’s behest.

The group then tried again to cajole Trump into issuing some sort of executive order, since Trump still appeared intrigued. But when Trump summoned Giuliani, the former president’s attorney said the gambit would work only in the event of clear foreign interference.

Powell, who had spent the previous weeks filing lawsuits alleging that Iran and China hacked into voting machines, sprang up and announced both to everyone in the room and a coterie of aides who had been dialled in on a conference call, that she had a file full of such evidence.

Giuliani looked at the documents but told Trump that Powell’s evidence was worthless, accusing her of producing one witness who was willing to testify about foreign election interference and around 10 who had simply signed affidavits saying they agreed.

Top advisers including Cipollone and Lyons have told associates they did not think the exchange about making Powell special counsel was serious. But Trump continued for days to mull the special counsel and voting machine ideas.

A spokesperson for Trump and a spokesperson for Cipollone did not respond to requests for comment. Powell, Giuliani and Lyons did not respond either. A spokesman for the select committee declined to comment on how the meeting might feature in its investigation.

Powell told associates she believed Trump made a decision to authorize her to be a special counsel of some nature. The following day, she called the White House chief of staff, Mark Meadows, saying she needed office space and a security clearance as the new special counsel.

Meadows did not refute Powell’s claim but told her he was working on logistics, and then called Giuliani to tell him Powell was trying to secure another audience with Trump. Giuliani told Meadows that Trump had barred Powell from the White House.

But while Meadows and other advisers had refused to grant Powell a “hard pass” that would have allowed her unfettered access to the complex, she returned to the White House on Sunday and Monday with documents on alleged Iranian threats to US election websites.

Meadows had revoked Ziegler’s access to the system for permitting White House access but Powell was cleared on a temporary “appointment” pass by another aide. She was, however, blocked from meeting the former president.