How will the presidential ‘nuclear football’ transfer to Biden if Trump leaves DC early?

Military officials will have second 45-pound briefcase ready for Joe Biden

Donald Trump will get to take the nuclear football with him when he leaves Washington DC on his final day in office – but the codes will be deactivated at the stroke of noon.

Mr Trump will be accompanied by the 45-pound briefcase when he flies to Florida on the morning of Joe Biden’s inauguration, as he is reportedly expected to do. 

But the nuclear codes that accompany it will stop working as soon as Mr Biden is sworn in as his successor 1,000 miles away on Wednesday.

Military officials will have a nuclear football, which contains the equipment the president uses to authenticate his orders and launch a nuclear strike, ready and waiting to accompany Mr Biden after he becomes the commander-in-chief, officials told CNN.

Mr Trump has also reportedly not made up his mind if he will continue the tradition of writing a letter to leave for his successor in the Oval Office’s Resolute desk.

There are a number of safeguards in place to ensure a smooth transition of control of the nuclear arsenal, says Stephen Schwartz, a nonresident senior fellow at the Bulletin of the Atomic Scientists.

"There are at least three to four identical 'footballs': one follows the president, one follows the vice president, and one traditionally is set aside for the designated survivor at events like inaugurations and State of the Union addresses," Mr Schwartz told CNN.

“On 20 January, the extra footballs will be out of town somewhere with their designees, leaving just Mike Pence's briefcase unless the White House Military Office has prepared (or already has on hand) another backup for Mr Biden.”

The president carries with him at all times a plastic card, known as “the biscuit," which contains codes that identify the president, who is the only person authorised to launch nuclear weapons.

The Constitution gives Mr Trump control of nuclear attacks until the very second that Mr Biden is sworn in at noon.

“Under the 20th amendment - and absent any invocation of the 25th amendment that would make Mike Pence the acting president -  Donald Trump is president through 11:59:59 am on 20 January,” added Mr Schwartz. 

"Up to that point in time, he has the sole, legal authority to authorize the use of any or all of the US nuclear arsenal.

“If an aide with the football accompanies Mr Trump on Air Force One to Florida, that aide will remove himself or herself from Mr Trump's presence at noon and return to Washington DC, with the briefcase.”

The outgoing president is expected to be at his Mar-a-Lago estate in Florida or nearby golf course when his term in office officially ends, reports CNN.

"The easiest way to think about it is there is a seamless cutover as to which 'biscuit' is valid at noon Wednesday," added Vipin Narang, a nuclear policy expert and professor at MIT. 

"Biden's biscuit would not be valid at 11:59 am, and Trump's would not be valid at 12:01 pm."

Mr Trump wants to hold a departure ceremony at Joint Base Andrews on the morning of Joe Biden’s inauguration before flying to Florida, say reports.

The ceremony may include a colour guard and even a 21-gun salute, officials told USA Today.

And there may also be a red carpet and a military band, according to The New York Times.

Mr Trump, who was impeached for an unprecedented second time on Wednesday, is expected to leave the White House for a final time early on inauguration day rather than attend the ceremony.

He will become the first president to snub his successor’s inauguration since the 1860s, but vice president Mike Pence has said he plans to attend.

Traditionally, the outgoing president has met with the incoming first family at the White House before the inauguration.