BONNIE GREER: Trump and Mueller face a gunfight at the D.C. Corrall

Their showdown is eagerly awaited by the nation and the world, and will define not only this administration but administrations to come. It will tell one and all something about the American soul.

Trump, the real estate mogul; the original ‘You’re Fired!’ guy from The Apprentice; purveyor of everything from beauty pageants to bottled water is in the Oval Office by virtue of an archaic voting system called the electoral college. Through it, the president is elected by the number of votes allotted to each State that he/she wins. Not by individual votes. That he lost the popular vote, a highly unusual occurrence, still grates on the man.

In fact, Trump himself railed against the electoral college for years until his strategists realised that this was the path that would win him the White House. The estimated 87,000 or so votes that got him victory in the electoral college is the stuff of nightmares for many and a legend for many, too.

And this deep, fundamental division is what the allegorical showdown at the O.K. Corral of the American soul is all about.

Garry Kasparov, the chess legend turned political activist, has labelled the 2016 US election the official indication that the US has entered an Age Of Chaos. He cites Russian president Vladimir Putin, a former KGB agent, as the purveyor of chaos. And what has been created is the mother of all stress tests.

Every US institution and norm is being tested. It becomes apparent every day just how much power the Congress has ceded to the executive. This existential good guy/bad guy gunfight has its roots at the time of the Vietnam War. It is the conflict that Mueller volunteered for. And the conflict that Trump avoided.

These two sons of powerful men, both from privileged backgrounds, born only two years apart, chose a different reaction to that war. It was the path to the O.K. Corral of today. One wore the white hat of the good guy. The other the black hat of the bad guy.

Mueller, the son of a DuPont executive and a graduate of Princeton, joined the U.S. Marine Corps in 1968, after a classmate was killed. He has stated that he and a few other friends decided to join up as a mark of solidarity and respect. Mueller waited a year for an injured knee to heal, waited so that he could serve.

It is said that he talks very little about his combat experience. Vietnam was the war that got no parades back home: no flag-waving in the streets, no pomp and no circumstance. For many Americans at the time the war was considered a shameful thing; a wasteful thing; a breaker-down not only of other people, but of America too.

But if you were drafted, you had to go. Unless you were wealthy and/or privileged. Like Robert Mueller and Donald Trump. Mueller chose to go. Trump chose not to. And he received a deferment five times. Which must be some sort of record.

Four of these deferments were for education, one was for medical reasons – bone spurs in his heels. The two daughters of a New York podiatrist have told the New York Times that their father gave the future president a medical excuse as a favour to his landlord: Fred Trump, Donald’s father.

The women claim that their father wanted to maintain access to Fred Trump in case things needed to be done in the building. They are not even sure that their father actually examined Trump.

Although this story has no verification, and the sisters are known to be fierce opponents of Trump, it is a fact that Fred Trump helped his son over the years to the tune of hundreds of millions of dollars. And when asked by journalists which foot had the bone spurs, Trump cannot recall. Although he claims to have one of the most phenomenal memories of all times.

The time Mueller was engaged in combat was the making of him. He is said to have a relentless discipline, honed in the Marines. He learned that to shave and make his bed every day, even in the midst of war, was a mark of discipline, of holding something of himself together.

Trump, on the other hand, is the man who has cited the New York clubbing scene of the 1970s and the 1980s as his personal Vietnam.

So the whole world now watches as Trump veers from one objective to another; a guy who can be swayed by a tweet, who can, as the saying goes, ‘turn on a dime’: change with rapid speed. He can go from conciliation one minute to becoming, in the next, the modern day equivalent of that Biblical line about when the Pharaoh’s heart hardened.

Mueller’s quiet relentlessness and consistency are legendary. Some say that he is fond of quoting that line in the 1995 thriller Crimson Tide: ‘We’re here to preserve democracy, not to practice it.’

His recurring nightmare is said to be Pan Am Flight 103 which blew up over Lockerbie 30 years ago. He wants to solve that once and for all.

In the 1990s, he was the assistant attorney general who took down the ‘Teflon Don’, the late head of New York City’s Gambino crime family, John Gotti. His second week as FBI director included the 9/11 terror attacks.

This metaphorical showdown, this meeting of two very different men, could bring about the definitive answer to a statement attributed to Benjamin Franklin more than two centuries ago.

The meetings that comprised the Constitutional Convention of 1787 were held in strict secrecy. As they drew to a close, anxious citizens gathered outside Independence Hall in Philadelphia to learn what had been produced behind closed doors.

Legend has it that a Mrs Powel asked Benjamin Franklin, ‘Well, Doctor, what have we got, a republic or a monarchy?’

Franklin responded, ‘A republic, if you can keep it.’

In 2019, America and the world will learn if the US was able to ‘keep it’.