Barry Levinson has produced some fine work, says Ryan Gilbey, but it's time he stopped chasing his own tail
The story of Barry Levinson isn't one in which a great artist suffers a tragic decline, and it may not even be a case of wasted potential; it doesn't fizzle out with a splutter like the careers of his contemporaries Michael Ritchie and Peter Bogdanovich, and its glories aren't confounded by perfectionism, as with James Toback. No: what has happened to Barry Levinson is that he has become renowned for being a mature, trustworthy and reliable film-maker. That's one of the worst fates that can befall you in Hollywood. You become a hired gun, or the man they call to iron out the creases in a troublesome product (as Levinson did when he took over Rain Man and Bugsy); you are respected because you serve your industry well, bringing palatable movies in on schedule and within budget. Naturally, you might warm to this state of affairs, and be reluctant to disrupt it. You may not even realise that you have come to represent the status quo that your early work set out to overturn.

This month, Levinson has two new films released within a fortnight: Sphere stars Dustin Hoffman and Sharon Stone, and is based on the novel by Michael Crichton; it is a big-budget, high-profile sci-fi thriller with shades of The Abyss. Opening today is Wag the Dog a modest political satire with Hoffman and Robert De Niro which was shot in under 30 days during a break from filming Sphere. Wag The Dog won't to change the world, but despite the banality of its attempts at satire, it does echo a more edgy style of film-making with which Levinson once seemed comfortable.

When his first and finest movie Diner was released in 1982, you felt as though a genuinely fresh voice had entered American cinema. Rooted in Levinson's home of Baltimore, the film was an unassuming but hauntingly honest portrait of four friends growing up in the late 1950s. Although it embraced nostalgia, it wasn't an ingratiating work - it didn't contrive melancholic friction between the past and present as American Graffiti had done before it. Driven by the vibrancy of dialogue and characterisation, it provided a respite from the calculated high-concept blockbuster, which had begun to hit its stride by the early 1980s.

Perhaps Levinson never intended to progress from the misty daydreams of Diner, though there was something about the movies which followed that suggested he was whiling away the hours polishing up on his craft as he waited for something better to come along. How else do you explain The Natural or Young Sherlock Holmes, films that made anonymity into an art form? He returned to Baltimore for the more personal comedy Tin Men, but his biggest commercial successes were lurking just around the corner. Good Morning Vietnam won him respect; Rain Man landed him an Oscar; each film is a testament to how unharnessed emotion in beats art and purity every time.

Yet still it's hard to believe that a man who has it in him to make a picture as sour and savage as Jimmy Hollywood - a fine satire on ambition and stardom, released in 1994 but a ghastly flop - can content himself with a career that is built out of sideways steps. There remain teasing suggestions that there is a film-maker alive and well inside that businessman's shell. Levinson got his fingers burned by the failure of Jimmy Hollywood, but he must learn to take such chances again, or risk being remembered more for his cameo as a psychotic bellboy in Mel Brooks' High Anxiety than as a director who knew what makes human beings tick.