At 10pm this evening, 200 years ago, Napoleon Bonaparte was narrowly defeated at the Battle of Waterloo by the English and the Prussians. And there is much speculation on the question: What if Napoleon had, instead, won that fateful battle?
How would it have altered the course of world history?
But there is perhaps another, more relevant, question to ask. Which is this:
After his defeat at Waterloo, Napoleon had made elaborate plans to escape to the United States - with whom he had excellent relations, because his revolutionary ideals resonated deeply with those of the US opinion leaders of the time. And moreover, because he had earlier sold to it, very cheaply, nearly 1,00,000 square miles of territory, from Louisiana up to Canada, which he had wrested from Spain (and for which the US was extremely grateful).
Napoleon's immediate plan, he said, was to go to the United States, and live as a private citizen, pursuing a life of science. But at the last moment, he - most uncharacteristically - quietly surrendered to the English, and was sent into exile on a remote island in the Atlantic, where he died a few years later, aged just 51. (Some historians claim that he was poisoned by the English, because he remained a threat to them as long as he lived.)
So the question is: What if Napoleon had indeed escaped to the United States, as planned?
What would have happened then?
We have to remember that Napoleon was one of the most remarkable leaders history has ever seen. He was, after all, the man who was France's greatest general at 28, the ruler of France at 30, and the man who had more or less conquered Europe before he was 40.
But that was just the military side of him: there was also the political and administrative side of him, which had introduced sweeping reforms across France, transforming its various structures, from administration to law, from education to finance. And, having done that, Napoleon was looking to create a unified Europe, which would have been a fore-runner of today's European Union - 150 years before its time.
He was a man, as French writer François-René de Chateaubriand noted, "of protean energy, grand purpose, literary talent, near-perfect recall, superb timing, inspiring leadership", and he went on to sum him up as "the mightiest breath that animated human clay".
So it's a bit difficult to think of a man like that sitting in a mansion in New Jersey spending the rest of his life in the innocuous pursuit of science (ha ha).
And certainly not when he was accompanied by a band of his close French aides, and backed by the one of the wealthiest, most influential men in the US, his French-born admirer, Stephen Girard. (There was also, of course, the very convenient $3 million he would be carrying with him - sufficient to finance an interesting range of future possibilities and ambitions.)
So the question is, what would Napoleon have done after getting to the US?
History suggests that sooner, rather than later, his restlessness would have drawn him west towards Texas, and the conflict that was simmering there with the Spanish - with all the opportunities it would have offered to a man with Napoleon's energies and leadership qualities (not to mention his military genius).
But Texas would surely be just the beginning.
From there Napoleon would most likely be drawn south into Mexico, which - having recently won its independence from Spain - was in chaos. In other words, the perfect opportunity for Napoleon's genius for administration and reform, backed by the hint of military muscle. And that would have taken him all the way down south to Panama.
But would that be sufficient for a man of Napoleon's great talents, and even greater ambitions? (After all, we're talking of the man who had envisioned the creation of a grand unified Europe, all the way from Lisbon to St Petersburg).
Well, by coincidence, he may well have been in the right place at the right time.
For at that time, right across the Isthmus of Panama, a war of independence was raging against the Spanish rulers, led by the famous revolutionary, Simon Bolivar - who just happened to have been a great admirer of Napoleon.
Bolivar is remembered as a skilled general and politician - but he was an amateur compared with Napoleon, and he probably knew it. He was often unsuccessful in his military campaigns, and when he ultimately managed to liberate five countries from the Spanish by the mid 1820s, he found he was unable to unite them, and administer them, as he had dreamed of doing, and ended up frittering away his opportunity.
So is it possible that that Bolivar would have invited Napoleon, his one-time idol, to join him in the campaign against Spain?
If so, the world could have well ended up in a situation where, by the age of 60, Napoleon would have marginalised Bolivar, and taken control of much of South America.
And then, marrying his political and administrative genius with the vast natural resources of the South American continent, he might well have laid the foundation for the superstate that he had originally planned for Europe - thereby laying the foundation for one of the world's great powers of the 20th century.
Just imagine how that would have changed the shape of our world today.
But, of course, it was not to be. Because, instead of carrying out his daring escape plan to the US that day in 1815, Napoleon, quite inexplicably, changed his mind at the last moment, and surrendered to Captain Maitland, commander of the HMS Bellephron, which was sailing off the waters of Rochefort.
A few years later, in exile on his remote island in the mid-Atlantic, Napoleon is said to have ruefully remarked to an aide, "My great mistake was to turn to the English and wind up on St Helena. If I was in America, everything would go well…."
Quite how well things would have gone for him we can only speculate today.