President-elect Donald Trump could be impeached over his hotel soiree with foreign diplomats, legal experts say

A Havard Uni law professor says President-elect Donald Trump's fresh gaffe breaches the US Constitution - and it could be his downfall. Photo / AP

It has a day spa named after Ivanka and a Presidential Suite to die for.

But the Trump International Hotel could bring the real estate mogul's time in the Oval Office to an abrupt end.

A Harvard Law professor has confirmed that President-elect Donald Trump could be impeached the moment he takes office, over comments made to foreign diplomats.

During a gathering at his new, spare-no-expense hotel in Washington DC, Trump wined and dined visiting officials in the opulence of the hotel's Lincoln Library, a junior ballroom with 4.8m ceilings and velvet drapes.

Ethical concerns were raised after a number of delegates admitted they would be tempted to stay at the hotel when visiting the US capital, in a bid to curry favour with the President.

"Believe me, all the delegations will go there," one Middle Eastern diplomat told the Washington Post.

"Why wouldn't I stay at his hotel blocks from the White House, so I can tell the new president, 'I love your new hotel!' Isn't it rude to come to his city and say, 'I am staying at your competitor?'" said another.

Trump built the hotel inside the former Post Office Pavilion, which his company leased from the US Federal Government in a 60-year deal worth US$180 million ($255m).

Commentators have flagged this as an "unprecedented and intolerable" conflict of interest that puts the integrity of federal procurement at risk, calling on Trump to step down from running his company or for the government to terminate the lease.

But legal experts are backing the possibility that the hotelier could face impeachment when he becomes President in January.

Richard Painter, a University of Minnesota law professor who served as chief ethics counsel to President George W. Bush, believes that Trump breached the US Constitution by schmoozing with diplomats at his swanky hotel.

The officials' attempt to get on Trump's good side by staying in his hotel "looks like a gift," Painter told ThinkProgress, which argued that the President-elect was "actively soliciting business from agents of foreign governments".

And toning down his approach once in office would not save Trump, the analysis said, because "the message that diplomats can earn the favour of the new President by staying in his hotels has already been received, and it can't exactly be unsaid".

ThinkProgress argues that this would breach the Constitution's Emoluments Clause, which states that federal officials may only do business with foreign government if they do not receive "special treatment", Painter said.

Harvard Professor of Constitutional Laurence Tribe weighted in on Twitter, backing the ThinkProgress analysis. If Trump was impeached, Vice President-elect Mike Pence would become take his place as President.

It is not the first time impeachment has been raised in regards to Trump. A law professor at the University of Utah has argued that the Trump University debacle alone is enough to impeach him on.

Article II of the US Constitution provides that the President "shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanours".

But, unless some kind of Republican conspiracy is afoot, it is unlikely to happen before 2018, since the GOP will control the House of Representatives and the Senate when Trump takes office.