The justice department called the ex-president’s claim of total immunity from prosecution “frightening”.
Judges expressed scepticism on Tuesday, as lawyers for Donald Trump presented a landmark case that ex-presidents should get immunity from criminal prosecution.
Mr Trump’s lawyers claimed his time in office protects him from charges connected to his alleged effort to overturn the 2020 election.
The justice department argued the presidency was not “above the law”.
Mr Trump, the frontrunner for the Republican presidential nomination, left the Iowa campaign trail to attend.
His motorcade slipped in and out of the Washington DC courthouse through a back garage and Mr Trump sat silently with his lawyers through the 75-minute hearing.
Speaking afterward from a local hotel, he said his side was “doing very well” in the case and claimed he was facing political persecution from the Biden administration.
The 77-year-old is accused by special counsel Jack Smith of trying to overturn President Joe Biden’s election victory in 2020.
The former president maintains that he should not face criminal charges because he was acting as president at the time. He has for years cited presidential immunity in his efforts to thwart civil and criminal cases brought against him.
This case, which will likely make its way to the US Supreme Court after this court’s ruling, could have a profound effect on the future of the American presidency and what is allowable by an individual who holds the office.
It may also delay Mr Trump’s criminal trial for weeks, if not months, during a fractious 2024 political campaign in which the former real estate mogul is a leading contender.
As soon as the case began, the three judges on the US Court of Appeals for the DC Circuit – Karen Henderson, J Michelle Childs and Florence Pan – asked probing questions about the implications of their decision.
Judge Pan, a Biden appointee, was particularly sceptical. She asked Mr Trump’s attorney, Dean John Sauer, whether he would contend that a president could order Navy SEALs – the elite US special forces – to assassinate a political rival, sell presidential pardons and state secrets or – in essence – act without being concerned with criminal prosecution.
Mr Sauer’s argument boiled down to the idea that a president who is not convicted for impeachment by Congress cannot be subject to criminal proceedings. Mr Trump, he noted, was impeached but never convicted by the US Senate.
But James Pearce, the government’s attorney, said such a precedent could easily be short-circuited and undermine Congress and any potential criminal proceedings. All a sitting president would have to do is resign before the legislature is able to begin impeachment proceedings to avoid prosecution, he said.
“What kind of world are we living in if… a president orders his SEAL team to assassinate a political rival and resigns, for example, before an impeachment – not a criminal act,” he said.
“A president sells a pardon, resigns or is not impeached? Not a crime,” Mr Pearce added. “I think that is an extraordinarily frightening future.”
More widely, Mr Sauer also contended that prosecuting a president for his actions in office could paralyse government, particularly the executive branch. He claimed that authorising “the prosecution of a president for his official acts would open a Pandora’s Box from which the nation may never recover”.
He posed the hypotheticals that George W Bush could be prosecuted for “giving false information to Congress” to make the case for the invasion of Iraq, and that Barack Obama could face charges “for allegedly authorising drone strikes targeting US citizens located abroad”.
While the judges seemed open to the government’s arguments, they also expressed concern that their decision could lead to the “Pandora’s Box” raised by Mr Trump’s attorneys.
Worried a broad ruling could create an opportunity for individuals to unnecessarily prosecute a future rival in the White House, Judges Henderson and Childs both asked how they might issue a ruling that would not “open the floodgates” to “tit-for-tat” prosecutions.
How they might narrow their decision is not immediately clear, however.
The decision made with regard to Mr Trump’s appeal will decide how a major American trial will continue and could have major implications for the office of the presidency.
The immunity defence has already been rejected by US District Court Judge Tanya Chutkan in December, who ruled that having served as president does not entitle one to a “lifelong ‘get-out-of-jail-free’ pass”.
In legal filings ahead of this hearing, Mr Smith, the special counsel, warned that a failure to allow Mr Trump to be prosecuted “threatens to license presidents to commit crimes to remain in office”.
In a fundraising email on Wednesday, Mr Trump said President Biden and Mr Smith were “attempting to strip” him of his rights.
A poll by CBS News suggests most Americans believe Mr Trump should not be protected from prosecution for actions he took while president.
The criminal trial in this election fraud case is scheduled for 4 March, but is on hold pending a ruling on the immunity claim.
The trio of judges on the DC appeals court comprise two judges appointed by Democratic presidents and one by a Republican, and is expected to deny Mr Trump’s appeal.
Whichever way the judges rule, the case is widely expected to end up in the US Supreme Court, where conservatives hold a 6-3 majority.