Theatre: The step-by-step guide to evil

Everyone knows it's good box office to put on a feel good show. It is also possible to break even in a subsided and small-scale theatre by putting on a feel-bad one. Few plays offer this prospect quite so wholeheartedly as C P Taylor's play Good, revived at the Donmar Warehouse, where it premiered in 1981. Good suggests that if we had been around in 1930s Germany, we too would have been Nazis.

Charles Dance plays Halder, a German professor of literature. His mother is ill, and he has written a novel that favours euthanasia. It has caught the attention of Hitler himself. This being the Donmar, the pivotal scene comes when the leading actor takes off his clothes. Dance removes his jacket, shirt and trousers and stands in his Persil-white vest and pants. We've been waiting for this costume change all evening.

What has made Taylor's play so promising is its gradualism. At each stage Dance believes he is doing the right thing. When Hitler comes to power, Dance tells his Jewish friend, Maurice, played with terrific exasperation by Ian Gelder, not to worry. The government, he says, will have to drop all that anti-Jewish stuff. When Dance goes along with the burning of books, he rationalises the event by saying that it's only a symbol. It doesn't mean anything. When he participates in Kristallnacht, he excuses it on the grounds that it will alert the Jews to the seriousness of their plight.

As Dance stands there, in his vest and underpants, his student girlfriend, Anne (the excellent Emilia Fox), helps him into his SS uniform. Nice Charles Dance, the sort of guy any young woman might think of introducing to her parents, is off to Upper Silesia to ensure that things are run efficiently at Auschwitz. Naturally, he thinks he is there to combat the outbreak of disease.

Dance is well-cast as Halder. A tall, courteous figure, with large hands and a questioning stare, he makes a plausible figure. He seems decent. He's candid about how exciting it is to join the party. Yes, he worries about the Jews, but they are not high on his list of worries.

This is where, structurally, Taylor's deft play is at its most effective. Taylor runs scenes concurrently to illustrate the competing claims on Halder's life. To join or not to join the party: that is only one concern. There is his mother's illness, his wife's neuroses, his affair with the student, his children and his job. Halder moves in and out of the overlapping scenes, addressing the audience as he goes. We are his conscience.

This is where Good fails. If we are expected to believe that we could be Halder, then we want to know, and very specifically, the steps that took him from a job teaching poetry at university to a job at the Nazis' largest concentration camp. It can't just be a sleight of hand. Dance's crimes are not mere sins of omission. To reach the point he does by the end of the play demands a certain careerism. Inertia, inadvertence and cowardice couldn't land him a post at the same workplace as Rudolph Hoess.

Taylor has presented Halder to us as a man of intellect. Yet we never see him jump through any intellectual hoops. Michael Grandage directs a strong cast in a dark, crisp and spare production. But Halder's journey is so quick and extreme that it loses its purchase on the audience. By the end I didn't feel half as complicit in his transformation as I had imagined I would.

Last week was an Oscar week in the theatre too. Moises Kaufman's play Gross Indecency - The Three Trials of Oscar Wilde was a hit off Broadway, and has transferred to the West End. Over here, Gross Indecency has to contend with our familiarity with the material: imagine taking Watergate or the O J trial to Broadway.

The Venezuelan director Kaufman runs a New York group, Tectonic Theatre Project, that aims to explore new theatrical language. The first surprise, as we take in the sump- tuous red curtains, lecterns and barristers' gowns and wigs, is the oldness of the theatrical language. The cast sit behind desks, hold up books and newspapers, and read quotes from biographies, memoirs and transcripts. There's a whiff of the lecture hall. This might be a very superior piece of Theatre-in-Education.

I'd read the script in advance and thought it terrific. Kaufman has fashioned a fast and affecting narrative from a collage of conflicting viewpoints. This demonstrates how many people were lying, either under oath, in their memoirs or to themselves. But it took half an hour before I was convinced that it was worth seeing Kaufman's script on stage.

A bewigged Michael Pennington plays Wilde with a pasty face and reddened lips that keep settling into an amused smile. He is excellent at catching Wilde's pleasure in parading his own intellect. In the first trial, his desire to show off is his downfall. It appals his lawyer, Sir Edward Clarke, played by Clive Francis, with a perfect legal mix of resonance and acuteness.

Thankfully, after the interval, Kaufman cuts loose, as the theatrical language turns abstract. There is a spoof interview with an American academic. Then the young men - the panthers with whom Wilde had feasted - loll across chairs suggestively and give evidence in their underwear while counsel cross-examine them from high above a turquoise curtain. As his world disintegrates, so does the style of presentation and Pennington's Wilde becomes an increasingly tragic figure. A powerful evening.

Swish-swish, swirl-swirl, crinkle-crinkle: in the new RSC Volpone at Stratford, taffeta billows round the stage like collapsing parachutes. And that's only what the guys are wearing. Each outfit could finance a student production of its own.

A strong-looking summer season at Stratford - with Alan Bates in Antony and Cleopatra and Timon of Athens - opens with Ben Jonson's exuberant satire on avarice. The highlight is Guy Henry as Volpone's servant Mosca who helps his master con people out of money, in the belief that Volpone is about to die and leave his wealth to them. Henry is a sonorous and saturnine figure (this Mosca likes his mascara) who manages simultaneously to be quick and composed. If they ever remake Chitty Chitty Bang Bang then this exotic willowy actor would be perfect for the childcatcher.

Elsewhere, Posner's cast keep slipping out of the groove. Some of them shout lines or nudge us with the idea they are playing amusing characters. This joviality muffles the dark, hard-edged clarity of the plot.

When the big moments come, they are only medium-sized. When Malcolm Storry's Volpone, with fox-red hair and grizzled beard, leaps out of bed and reveals to Claire Price's Celia that he isn't a sick old geezer at all and wants to have sex with her right now, it's not the hilarious revelation it might be (from where I was sitting, at the crucial moment, neither face was visible). When the husband Corvino threatens to beat Celia or Volpone tries to rape Celia, we don't feel chilled by the extremity of their behaviour. Moment after moment falls a little short or a little long of the brisk ruthlessness of Jonson's satire.

`Good': Donmar, WC2 (0171 369 1732) to 22 May. `Gross Indecency': Gielgud, W1 (0171 494 5065) booking to 12 June. `Volpone': Stratford Swan (01789 295623) to 9 October.