Madonna still a music legend

When Madonna looks back, as she might on her 46th birthday on Monday, she may feel satisfied that her life, career and celebrity have always been about music - even if she has often given the appearance of believing that music is secondary to her current fad.

And what fads she has had. The early need to shock. An acting career notable chiefly for director John Schlesinger's claims that her impossible behaviour on the set of The Next Best Thing contributed to his heart attack. Her vanity label Maverick (which spawned Alanis Morissette's multi-millionselling Jagged Little Pill), her plodding children's books, and her latest hobby, the self-indulgent Kabbalah cult. Ultimately, Madonna is good at music and little else.

Re- Invention, her fifth "world" tour, which began in Los Angeles in May, has been a roaring success. The European leg opens tomorrow evening in Manchester's cavernous MEN Arena, and arrives in London next Wednesday.

Nevertheless, it appears that Madonna's astonishing career is in its twilight. The signs are unmissable. For a start, there is no new album to accompany the tour. All her previous world-encirclers - Who's That Girl, Blond Ambition, The Girlie Show and Drowned World - have been heralded by new material. Then there is the shrinkage. Her world now consists of the United States, Canada, England, Ireland, France and the Netherlands. Beyond Britain, where two MEN Arena dates, two at Earl's Court and four at Wembley Arena have sold out, her appeal is receding.

Finally, there is her compromise. When the tour was announced in January, it was called Whore of Babylon. Somewhere along the way, Madonna renamed it. What about 1992's author of the graphic and controversial book, Sex; 1990's simulator of masturbation on-stage every night of Blond Ambition; 1991's star of the remarkable documentary, In Bed with Madonna; 1994's 13-times pronouncer of "fuck" on David Letterman's prime-time US network television show: would that Madonna have watered down her title? I think we know the answer.

Like every major artist (with the possible exception of Bob Dylan) who has sold millions of records over decades and become part of society's wallpaper, Madonna has surrendered her cultural resonance in exchange for celebrity. Her cultural resonance was all about her music. Perhaps because she came to New York from Michigan to dance rather than to sing, she approached music as an outsider and became a nimble magpie. She had the unerring ability to lead trends in genre (dance, electro), fashion (vogueing) and social mores (the manner in which sexual display became explicit). She was never the first on the block, but she was always the canniest.

Spotlighted in re-Invention, the watertight Holiday, her third single and first hit (in 1983) was dance at its cutting edge. By pumping out disco singles in an era when disco was box-office poison and by assuming the role of a less kooky Cyndi Lauper, Madonna muscled her way to the front of the queue. Pleasant as Borderline and Lucky Star were to the ear, there was little to distinguish their co-author from her competitors in SOS Band or Indeep. But, then everything coalesced. Songwriters Tom Kelly and Billy Steinberg's Like a Virgin turned Madonna into a phenomenon. She well understood that the word " virgin" matched with her distinctly unvirginal attire would cause a furore. She ended up on the cover of Time magazine and the Like a Virgin album topped US and UK charts.

Suddenly, every little thing she did was magic. The singles were unstoppable, whether hard-nosed odes to consumerism (Material Girl) or chubby ballads (Crazy for You, Live to Tell). More importantly, she was intermittently brilliant.

Listen to Into the Groove, which, perhaps uniquely in popular music, was so urgent that it did not have an instrumental break. In its own way, it was as revolutionary as the grunge classic, Smells Like Teen Spirit. Then, when she flirted with Latin music on La Isla Bonita, she scored more success in four minutes than Gloria Estefan had managed in 30 years.

In 1989 came her most musically sophisticated moment, Like a Prayer. This wonderful song's video portrayed Jesus Christ as a black man. It managed to outrage Pepsi (who withdrew sponsorship), Muslims (who issued fatwas) and the Vatican (which demanded to have her banned from Italy, land of her forefathers).

This was Madonna at her musical, cultural and political zenith. The world was listening but, distracted by her acting ambitions, Madonna lost the plot. Once she owned the world, then her moment passed and, with it, her rigour. What followed was hit and miss. From Like a Prayer, it was a small step to Hanky Panky (distressingly retained in re-Invention), Rescue Me and a disastrous, lumpen cover of Fever.

Her most recent albums, Music, Ray of Light and American Life, bore flashes of the real Madonna, but her days as a pioneer were gone and so was her moment: she hired the cutting-edge William Orbit to co-produce Ray of Light at the very instant that his star had begun to fall.

Although she will endure as a megastar, Madonna's musical legacy is surprisingly slender: just nine studio albums in 24 years (excluding countless hit collections, remixes and soundtracks), none of them undeniably great and two (Bedtime Stories and Erotica) utterly wretched. Yet, it is the music that made her. And despite herself, it always will be.