Before her death, the fortunes of the Windsors had been in steady decline. Apotheosized by Queen Victoria in the 19th century as models of a stolid, faintly Germanic rectitude, the family began to appear irrelevant by the 1960s and ’70s. With its country piles, its salmon streams and grouse moors, it seemed antique in a Britain already adopting American habits of permanent change. Its tacit reinforcement of the class system offended ambitious men and women–notably Margaret Thatcher, for whom the royals gave aid and comfort to the ““Tory grandees’’ she so loathed.

Into this vacuum of spirit and style came the vibrant, 19-year-old Diana Spencer. Once Prince Charles decided on her as future queen and mother of his heirs, Buckingham Palace spied an opportunity. Thoroughly Modern Diana would update the House of Windsor. A cheeky 1992 article in The Economist treated the Windsors as a business firm diversifying into ““younger brands,’’ and warned of trouble as it increasingly departed from its ““core business’’ of ancient ceremony and traditional decorum to deliver ““mass entertainment.’’ The result was a glare of publicity that relentlessly exposed the family’s flaws, from Charles’s New Age musings to the marital mishaps that plagued Charles, his sister, Anne, and his brother, Andrew, alike.

It was always a dangerous strategy. As an earlier editor of The Economist, the eminently Victorian Walter Bagehot, put it in his classic 1867 book ““The English Constitution,’’ ““Above all things our royalty is to be reverenced, and if you begin to poke about it you cannot reverence it . . . Its mystery is its life. We must not let in daylight upon magic.’’ The Queen Mother made the same point more bluntly when Elizabeth II decided to let television cameras into Buckingham Palace in the late 1960s. It was a historic blunder, she reportedly told her daughter: ““Never let them in. Never.’’ The queen went ahead anyway. In 1992, looking back over what she called an ““annus horribilis’’ (horrible year) for the royal family, she conceded that ““criticism is good for people and institutions that are part of public life. No institutions–City [the London financial district], monarchy, whatever–should expect to be free from the scrutiny of those who give it their loyalty and support, not to mention those who don’t.''

Such gestures won the Windsors few new friends. The slide continued. Last month a poll published in The Guardian newspaper announced that fewer than half of Britons surveyed said the country would be worse off without the royals–a drop from 70 percent just three years ago. More worrisome for the palace, more than a third of respondents between the ages of 18 and 24 said Britain would actually be better off–precisely the generation Diana was supposed to attract. Another poll earlier in the year found only one out of five Britons believing that the family was ““concerned about people in real need.’’ Diana herself drew attention to the disaffection. ““Someone’s got to go out there and love the people and show it,’’ she said in 1995, explaining her freelance missions to the ill and the afflicted. She didn’t actually accuse the other royals of remoteness. She didn’t have to.

Charles, at least, has been trying to narrow the gap. He has always had a civic spirit, from his jawboning of businesses to rebuild tapped-out mill towns to his environmentalism to his complaints about the esthetic poverty of much postmodern architecture. In the 1980s he even became something of an irritant to the Thatcher government (though he reportedly enjoyed amicable relations with Thatcher herself). Lately Charles has stepped up his personal involvement in The Prince’s Trust, an umbrella group of charities, and Business in the Community, a project devoted to creating jobs through local initiative and self-help. But as long as Diana was drawing the spotlight, there wasn’t room for both of them. Charles was, as acquaintances liked to say, doomed to play a largely walk-on role as ““Mr. Diana.''

Now he stands alone with his children. The British people will rally round them, partly from sheer sympathy but partly, too, because whatever magic is left in the monarchy now descends on them. Bagehot’s words seem quaint today: does anyone believe in magic anymore? The answer is that not to believe in magic at all is not to believe in the appeal of Princess Diana. Could she have commanded such loyalty as plain Diana Spencer, Sloane Ranger and friend of Fergie’s? Clearly not. Diana was Diana because she was a princess in a culture where the idea of a princess still summons for substantial numbers of people what Abraham Lincoln called ““the mystic chords of memory.''

Prince Charles cannot hope to inspire the affection Diana did. But he is heir to a throne that serves a public purpose. As Bagehot noted long ago, the ““genius’’ of the British people is theatrical; it cares for ““the outward show of life’’ as well as the practical ““substance of things.’’ As a result, it has over the centuries devised a peculiar division of labor in public life: it assigns to its political leaders the substance of things while reserving for its monarchs the realm of the theatrical, the symbolic. The arrangement allows both change and continuity. Prime ministers come and go; the monarchy endures. And because the monarchy endures as an embodiment of the nation, citizens can attack their political leaders without feeling somehow disloyal. It is a feature other countries might well envy–for example, the emerging democracies of Eastern Europe, which lack the notion of loyal opposition to the government of the moment.

The danger for the British monarchy is that more and more people will attack it as though it were a mere government of the moment, with no more permanence than a prime minister has. Some of the opinion polls suggest trends in this direction. The burden now is on Charles to re-establish the throne as a seat of continuity. It will not be easy. The magic still exists, as the life and death of Princess Diana demonstrate. But will Charles prove worthy of it?