COMMENT

Heredity matters. All 109,000 of the baby boys born last Wednesday (yes, that's roughly how many get born every day around the world) will have inherited a Y chromosome from their fathers. All will have inherited a combination of genes from both their parents, and these genes will determine every-thing from the colour of their hair to their aptitude for mathematics, maybe even their sexual proclivities in adulthood. An unlucky few will inherit some hereditary defect or disease. By contrast, a lucky few will, in the course of their lives, inherit fortunes, the size of which will depend on the acumen (or the luck) of their parents and the laws governing inheritance, not to mention the taxes on it, in the country of their birth or later residence.

But only one of these baby boys stands to inherit an imperial title and throne: a Chrysanthemum Throne, no less. He is the son who was born on September 6 to the Japanese Princess Kiko, wife of the reigning Emperor Akihito's second son. Should his uncle, the crown prince Naruhito, die without a male heir — as seems likely, since his wife has produced a solitary girl and recently suffered a nervous breakdown — then this wee lad will one day be the Emperor of Japan.

To Americans, it all seems absurd. What could be sillier than permanently to confer a title like "Emperor" on the members of a single family, and only the males at that. (The fact that the baby was a boy allows the Japanese government to shelve a Bill that would have permitted female succession.) And yet the Japanese are hardly unique in having a hereditary monarchy based on the rule of primogeniture. We have been doing it in this country for more than a millennium, since the time of Egbert (802-839).

Unlike their Japanese counterparts, to be sure, the British Royal Family cannot claim an unbroken line of succession, nor a divine progenitor (the sun goddess Amaterasu Omikami, no less). Mainly on account of his Roman Catholicism, James II was ousted from the throne in 1688 by a parliamentary coup d'état, which also denied his son, grandson and subsequent male heirs their birthright.

Still, no one aside from a few diehard Jacobites seriously disputes the legitimacy of today's House of Windsor, as the Saxe-Coburg-Gothas renamed themselves during the First World War. It is the legitimacy of monarchy as an institution per se that, in moments of crisis, the British debate.

One such moment came in the aftermath of the death of Diana, Princess of Wales. A new film, Stephen Frears's The Queen, which stars the incomparable Helen Mirren in the lead role, may re-ignite that strange row, which pitted traditional monarchists, who had come to regard Diana as a renegade in league with the tabloids, against Mills & Boon republicans, who adored her with such cultish devotion that they were ready to torch "the Palace" to avenge her supposed mistreatment.

The real Queen, whom, if Frears is to be believed, her husband calls "cabbage" as a term of endearment, has striven mightily to repair the damage done by the Diana disaster. Much has been achieved by her and other members of the Royal Family. But the foundation on which the British monarchy rests has been weakened. Too much doubt has been cast on the hereditary principle by the transformation of the House of Lords from an authentically aristocratic upper house into a London club for the financiers of political parties.

The principle of hereditary status has come to seem absurd, even as the practice of hereditary wealth, which socialists once sought to abolish, has made a remarkable comeback.

Is there an antidote, a way of stopping the monarchy going the way of the hereditary peerage? Perhaps. After all, monarchy must be quite resilient as an institution. The success of the United States after 1776 was certainly a great advertisement for republicanism. Contrary to classical political theory – and to the experience of France after 1789 – democracy never gave way to tyranny in America. And yet a surprisingly large number of countries today, more than 200 years later, have chosen not to follow the American example. In all, there are currently 45 nations in the world with monarchs as heads of state, which is roughly one in four of the world's countries.

In some cases, like Saudi Arabia, the king is a true sovereign; indeed, he and the other monarchs of the Gulf region are all but absolute rulers. In other cases, constitutional conventions have eroded the monarch's power, though one consequence of this political diminution has been to preserve the Queen's status as head of state in a remarkably extensive group of 16 former British colonies.

Nor is monarchy merely an idiosyncrasy of Arabs and Britons alone. The European Union likes to present itself as the last word in constitutional post-modernity, yet six of its members (besides Britain) are monarchies: Belgium, Denmark, Luxembourg, the Netherlands, Spain and Sweden.

The great puzzle is why all these countries have clung on to a political institution that, to its detractors, seems hopelessly anachronistic. Edmund Burke's answer, in his Reflections on the Revolution in France, was that the hereditary principle had one advantage over popular election: namely, that monarchs ought to be more mindful of the interests of future generations (if only their own descendants) than elected heads of state, whose time-horizon may be as short as four years. As Burke put it, turning Jean-Jacques Rousseau on his head, the real social contract is not a short-term deal between a ruler and "the popular will", but is an enduring partnership with generations to come.

People may mock Prince Charles for his passionate commitment to environmental and architectural conservation. They fail to see that he is mindful of precisely that Burkean partnership with the distant future.

Not convinced? There's another argument. Consider the remarkable smoothness with which the crown has passed from monarch to heir throughout the period since 1688. Despite the inevitable duds that arise in any hereditary system — the ones who die childless, or marry unwisely, or are too thick, or too clever by half — the history of modern British monarchy has been one of near-seamless transition.

Now compare the way in which the elected office of prime minister has changed hands in the same interval. As I write, we are somewhere in the middle of round 92 of the most wearisome heavyweight contest in the history of British politics. The fading champion, Tony Blair, is out on his feet, but the challenger, Gordon Brown, seems almost as punch-drunk. They cling to each other in the middle of the ring, alternately propping one another up and landing the occasional feeble punch. If the challenger were any good, it would all have been over long ago. Worse, the ringside is crowded with would-be contenders, eager to turn the fight into a free-for-all.

Of course, I do not say that succession crises do not also occur in monarchical systems: think only of Henry VI, deposed and imprisoned by his cousin Edward IV. When the stakes are high, whether in an absolute monarchy or an elective dictatorship, the likelihood of ugly scenes will also be high. Nevertheless, I would hypothesise that, taking all the world's polities over the past hundred years, the world's republics have, on average, witnessed more succession crises than the world's monarchies.

For the reality is that the United States remains quite exceptional in the durability and (one civil war aside) stability of its republican institutions. Few other republics would have come through the knife-edge election of 2000 without a shot being fired. Only think what is currently happening in Mexico, where the loser in July's very close presidential election is talking openly and ominously of "civil resistance".

Kings — and queens — have their shortcomings. They can seem a little quaint. But maybe there are worse ways of choosing a successor than good old blood lineage.

• Niall Ferguson is Laurence A. Tisch Professor of History at Harvard University and Senior Fellow of Jesus College, Oxford. His new book, The War of the World: History's Age of Hatred, has just been published by Penguin Books. www.niallferguson.org

© Niall Ferguson, 2006

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