THE GOOD NEWS? IT’S NOT AS EASY AS PRESSING A BUTTON

WHEN Donald Trump boasts about the size of his nuclear button, he will have sent shivers down the spine of the US defence establishment. Officials have long worried about the ease with which a belligerent or unstable president can launch a nuclear attack.

So how does it work? Wherever the leader of the free world goes, a nondescript black briefcase carried by a military aide is always a few steps behind – only a leather leash running from the handle to the bearer’s wrist hints at the importance of its contents.

Officially known as the ‘President’s emergency satchel’ – unofficially it’s the ‘nuclear football’ – it contains the so-called ‘gold codes’ that allow him or her to launch a devastating nuclear attack anywhere in the world in just a few minutes. So what does this mean for a man as notoriously impetuous as Trump? Hillary Clinton wasn’t alone when she fretted that ‘a man who can be provoked by a tweet should not have his fingers anywhere near the nuclear codes’.

And indeed, Trump has repeatedly threatened North Korea and its ‘short and fat’ leader Kim JongUn with obliteration, warning that the US could ‘unleash fire and fury like the world has never seen’.

The original architects of the American nuclear weapons system were worried chiefly by the threat of a Soviet first strike, which would give America an estimated six minutes to respond before it was hit and its own arsenal wiped out.

The possibility that the president would have to react immensely quickly has given the office-holder the prerogative to act entirely on his own initiative. No consultation, let alone approval, is needed before launching a nuclear strike.

Once the president has properly identified himself to the Pentagon war room, his order for a nuclear strike must be obeyed. There is only one constraint – the order must be ‘constitutional’, which means the President believes he is acting to protect the US against actual or imminent attack. There are no legal or procedural grounds for his military commanders to disobey a nuclear strike order.

The current situation isn’t the first time senior Washington officials have worried about an unreliable president. As Richard Nixon became increasingly unhinged and hard-drinking during the Watergate scandal in the early 1970s, his defence secretary James Schlesinger quietly ordered the Pentagon war room to tell him if Nixon contacted it to order a nuclear strike.

At least there is no actual button the president can press – the process is more elaborate than that.

The ‘nuclear football’ got its name from an Eisenhower-era nuclear war plan code-named ‘Dropkick’. There are actually three ‘footballs’ – one briefcase that travels with the president, another accompanying the vice-president and a spare stored in the White House.

Each of the ‘ball carriers’ is issued a Beretta 9mm pistol, and has orders to shoot anyone who tries to grab the briefcase. It is further secured with a combination lock.

The contents are classified and have changed over the years, but an antenna is sometimes seen sticking out of the top – suggesting the bag contains a satellite phone.

It also contains a 3in-by-5in laminated card sealed within a plastic strip which has to be cracked open. This is the ‘biscuit’, resembling an oversized credit card and inscribed with a column of codes made up of numbers and letters. The president must memorise where to look on the card for the ‘gold code’.

By reciting the code down a secure line to the National Military Command Centre in the Pentagon, the president authenticates himself as the commander-in-chief and can give a nuclear launch order.

Astonishingly, during several previous presidencies, that card has occasionally gone missing.

In the late 1970s, Jimmy Carter once left the codes card in a suit that was sent to the dry cleaners. His successor, Ronald Reagan, though, could hardly be blamed when he, too, mislaid the card.

When he was shot in 1981, he was stripped of his clothes and possessions as he was wheeled into surgery. The card was later found in a hospital plastic bag. Bill Clinton lost his card at least twice.

Given Donald Trump’s childish rhetoric this week, one wonders if his military aides are rather hoping he mislays the nuclear codes, too.