TORONTO -- One of the heaviest responsibilities of the U.S. presidency is access to the so-called "nuclear football" – the codes that confirm a president's identity and allow him to launch the country's nuclear arsenal.

Physical possession of the codes is normally left to a military aide who trails a short distance behind the president, holding onto what is called the "president's emergency satchel."

On inauguration day, the process of getting the codes to the new president is straightforward: one military aide, assigned to the outgoing president, passes the satchel to an aide assigned to the incoming president.

This year, though, that isn't an option. With outgoing President Donald Trump skipping president-elect Joe Biden's inauguration ceremony to instead spend the afternoon in Florida, a literal handoff of the nuclear codes is not possible.

Instead, CTV News international security correspondent Jeanne Meserve explained Wednesday on a CTV News broadcast, the U.S. military has designed a "more complicated" handover involving two separate black bags.

One of those bags travelled to Florida with Trump, Meserve said, in case he feels the need to launch nuclear weapons before Biden is sworn in. Another bag, containing different authentication codes, will be at the inauguration ceremony.

"At noon, the set of codes that Donald Trump has will become inactive – and at that moment, the set of codes that Joseph Biden has will become active," Meserve said.

It is not unusual for there to be multiple "nuclear footballs" in play at once. In addition to the one that stays with the president, one satchel is kept near the vice-president at all times. Another is placed with the "designated survivor" left behind during state of the union addresses.