LONDON - "We know no spectacle so ridiculous," opined the great nineteenth-century historian, Thomas Babington Macauley, "as the British public in one of its periodic fits of morality." But for sheer ridiculousness, few spectacles are quite so grimly moronic as the American media plunging overboard in one of its periodic obsessions with the British House of Windsor. The news - to use the term in its most limited sense - that the Duke and Duchess of Cambridge expect their first child to arrive sometime next summer is sending a good part of the American press into a familiar frenzy of twittering, fluttering excitement.

Mark Twain was right. "Unquestionably the person that can get lowest down in cringing before royalty and nobility, and can get most satisfaction out of crawling on his belly before them, is an American. Not all Americans, but when an American does it he makes competition impossible." Consider that Twain never had the pleasure of witnessing American morning television and its ridiculous habit of fawning over, successively, Prince William's engagement, his marriage to Kate Middleton and, now, the happy news that the next stage of the succession is on the point of being secured.

When Queen Elizabeth made a state visit to Washington in 2007, my, how members of the capital's elite scrambled for the merest glimpse of royal flesh. At a garden party hosted by the British embassy, members of Congress and what remains of Georgetown society could have been mistaken for teenage girls queuing for tickets to see "One Direction."

The American fascination with the British royals is hardly new, even if it has been magnified by a culture ever more in thrall to celebrity. Much of the rot set in with Princess Diana, whose "fairytale" wedding to Prince Charles descended into a gruesome - if compelling - soap opera.

Diana died before her story became too tawdry. Her demise allowed attention to pass to the next generation and to Prince William in particular. His wedding in 2011 to Kate Middleton - a commoner, no less! What a fairytale! - was an event crying out for mawkish excess. American television fell upon the challenge in splendid style. The morning shows decamped to London for a week of newlywed overkill. As purveyors of mindless tommyrot, "Good Morning America" was in its element as it offered Americans the opportunity to gawk at all the princely finery, pomp and flummery on display in Ye Olde London Town. There is something ghastly about this.

Ghastly but not, alas, un-American. There is no novelty in observing that much of American culture thirsts for aristocracy to an extent that is sometimes hard to find in the United Kingdom. To cite Twain again: "We have to be despised by somebody whom we regard as above us or we are not happy; we have to have somebody to worship and envy or we cannot be content. In America we manifest this in all the ancient and customary ways. In public we scoff at titles and hereditary privilege but privately we hanker after them, and when we get a chance we buy them for cash and a daughter."

Can anyone doubt the truth of this? The imperial presidency has been a sorry fact for decades now. How can it be otherwise when the mere mortal elected to the presidency is treated - at least in terms of expectations - as some kind of priest-king?

Not that it ends there. Congress has become a family business in which promotion is based on genes more than ability. The British House of Lords may be an anachronism, but at least it recognizes inherited power as, well, an anachronism. From the Kennedys to the Pauls via the Udalls, the Murkowskis, the Jacksons and many others, political privilege in modern America often seems to have become a matter of inheritance.

More broadly, the elites are, in some respect, more isolated from the American mainstream than at any point in the nation's history. Witness, for example, the widespread sense on Wall Street that President Barack Obama was implacably hostile to America's super-rich. Witness too how much more ink is spilled debating affirmative action than contemplating legacy admissions to America's greatest universities. Anything that inconveniences the elite is, apparently, "class warfare."

It is one thing for Britons - or Canadians or Australians - to take some interest in Kate's pregnancy. The infant will, some distant day, be expected to be our monarch. Americans have no such excuse. Is there not something mildly shameful, something plausibly demeaning, about this excessive fascination with another country's ruling dynasty?

Benjamin Franklin's challenge to the new-born United States always carried a whiff of pessimism about it. "A Republic, if you can keep it," he warned. In truth, that kind of astringent republicanism perished long ago. Today, the goggle-eyed, breathless fascination with Kate Middleton's womb is perhaps but another reminder of the extent to which American exceptionalism, in this respect at least, is no longer quite as exceptional as once it was.

Alex Massie writes for the Spectator. He wrote this for Foreign Policy.