Flynn, recently pardoned by Mr Trump after his Russia investigation conviction, told Newsmax martial law was not “unprecedented” as he laid out his case for military involvement in the democratic process.
During Friday’s White House meeting, at which Flynn was present, Mr Trump asked aides how martial law works, sources told the New York Times.
According to the NYT report, Mr Trump also suggested naming Sidney Powell, a lawyer and ally who has pushed his false election claims, as a special counsel overseeing alleged voter fraud at the election.
The White House counsel, Pat Cipollone, and White House chief of staff, Mark Meadows – and other top advisers – opposed the ideas being put forward at the meeting, saying there was no constitutional authority for them, the NYT reported.
In response to Flynn’s calls to invoke martial law, army secretary Ryan McCarthy and chief of staff general James McConville issued a joint statement saying there “is no role for the US military in determining the outcome of an American election”.
It was not immediately clear if the president plans to press ahead with appointing Ms Powell as a special counsel.
Mr Trump responded to the martial law claim early on Sunday morning, describing it on Twitter as “Fake News”. “Just more knowingly bad reporting!” he added.
Despite the electoral college (EC) meeting last week to certify Mr Biden’s election victory, the defeated incumbent continues to falsely insist that the won and that the 3 November poll was “stolen” from him.
The president and his legal team continue to allege, without evidence, that mass voter fraud took place in key swing states across the country.
Thousands of Mr Trump’s supporters took to the streets last week in a show of support of those baseless claims, with violent clashes breaking out in state capitals across the US.
And there is another protest planned to take place on 6 January, the day Congress meets to officially recognise Joe Biden as president following the 14 December EC vote.
As the coronavirus continues to ravage vast swathes of the country, the outgoing president called on his legion of loyal fans to descend on the capital and join the demonstration.
“Big protest in D.C. on January 6th,” he tweeted on Saturday. “Be there, will be wild!”
Mr Trump’s campaign and his allies have now filed roughly 50 lawsuits alleging widespread voting fraud and almost all have been dismissed or dropped.
Team Trump has lost before judges of both political parties, including some he appointed, and some of the strongest rebukes have come from conservative Republicans.
The Supreme Court has also refused to take up two cases — decisions that the president has scorned.
With no further tenable legal recourse, Mr Trump has been fuming and peppering allies for options as he refuses to accept his loss.
That includes his personal lawyer, Rudy Giuliani, who during the Friday meeting pushed the president to seize voting machines in his hunt for evidence of fraud.
The Department of Homeland Security made clear, however, that it had no authority to do so. It is also unclear what that would accomplish.
Sacked attorney general William Barr earlier this month said that the Departments of Justice and Homeland Security have looked into claims that voting machines “were programmed essentially to skew the election results … and so far, we haven’t seen anything to substantiate that.”
Paper ballots are also retained under federal law and have been used to verify results, including in Georgia, which performed two audits of the vote tally using paper-ballot backups.
Ms Powell was initially part of the president’s campaign legal team but was booted out after a bizarre news conference with Giuliani in which she made a series of outlandish claims of election fraud, including an assertion that election software was created in Venezuela “at the direction of Hugo Chavez” — the Venezuelan president who died in 2013.
In interviews and appearances, Ms Powell continued to make misleading statements about the voting process, unfurled unsupported and complex conspiracy theories involving communist regimes and vowed to “blow up” Georgia with a “biblical” court filing.
Trump’s team soon announced it had cut ties with Ms Powell. “She is not a member of the Trump Legal Team. She is also not a lawyer for the President in his personal capacity,” Giuliani and another Trump lawyer, Jenna Ellis, said in a statement.
Dominion Voting Systems, a particular target of Ms Powell’s, has also demanded she retract the “wild” and “knowingly baseless” claims she has made about the voting machine company and threatened a defamation lawsuit.
Since parting ways with the campaign, Powell has continued to file litigation on Trump’s behalf, teaming up with conservative attorney L. Lin Wood in Georgia.
Ms Powell and the White House did not respond to requests for comment on Saturday.
Additional reporting by Associated Press