THEATRE / Coming under friendly fire: Paul Taylor on Sam Shepard's States of Shock in Salisbury and Trevor Griffiths' Comedians in London

THE AMERICAN flags have undergone a macabre transformation. Frozen in mid-flutter, they have turned, creepily, into their own X- rays, revealing human skulls and bits of bone in place of stars and stripes. Down on the ground, it looks as if there's been an explosion at a photographic developers. Like so many mutilation cases, thousands of shredded snaps litter the stage, stirring eerily to the poundings of periodic bombardments. Add the tent-like appearance of the place and its rum clientele (a couple of corpse-white customers waiting for their clam chowder as if for Godot), and you feel fairly safe in assuming that this is no ordinary 'anonymous American diner'.

States of Shock - now receiving its English premiere at the Salisbury Playhouse in Deborah Paige's blistering co-production with the National Theatre Studio - has been described as Sam Shepard's response to the Gulf War, though that conflict is the play's provocation rather than its subject (which is more generalised and mythic). The biblical story of Abraham's readiness to obey God and kill his son Isaac has often been co-opted to serve as a parable of war on the generation gap, the military and political old guard sacrificing the country's youth on the altar of suspect ideals. Wilfred Owen, for example, wrote a poem on these lines and the parable came in for some blackly comic reinspection recently in Bill Morrison's Ulster trilogy. Never before, though, has it been dealt with in such a fractured, zany, lacerating way as here.

The mood from the start is an odd mix of the dippy and the dark. To commemorate the first anniversary of his soldier son's death in desert crossfire, the Colonel (David Burke) wheels into the diner a young veteran named Stubbs (Corey Johnson), who was crippled and rendered impotent by a bullet that passed straight through his body before killing the Colonel's son. Two banana splits with a giant candle in each may seem a pretty surreal way of marking the occasion, but then, under the septic waggishness of the Colonel, you sense suppressed guilt. His persistent efforts to secure a precise account of the episode from the young man has the paradoxical feel of a furtive cover-up. It's as if he wants to plant his own version of events in the youth's mind.

For a time, you imagine that the Colonel, a dogged defender of American imperialism, can't face the idea that his son was shot in a 'friendly fire' incident. But then as power shifts to the young man (regenerated, it seems, by a roll around the floor with the waitress) weirder possibilities arise. Clinging to his original version with a mounting, panicky bluster, David Burke's wonderfully deranged Colonel is confronted with an alternative scenario. Perhaps he invented his son's death and it is Stubbs, the traumatised wheelchair-bound victim, not the dead hero, who is his progeny; perhaps their falsified new relationship is a desperate exercise in paternal evasion. But whether as a real or a symbolic father, the Colonel, it emerges, abandoned Stubbs on the battlefield. Hence the final tableau in which (in a pointed reversal of Abraham / Isaac iconography) Stubbs rears up over the Colonel with a drawn sword.

'I miss the Cold War with all my heart,' muses the waitress at one point. In States of Shock, Shepard creates an exaggerated but authentic-seeming world in which people feel more comfortable contemplating an acknowledged enemy than a friend or son. A return to the author's earlier style, the play is written with a free-wheeling, wacky savagery and deserves an audience larger than the 15 who were there the night I saw it. In The Gulf Between Us, Trevor Griffiths also responded to the war in (muted) magically realist mode, but less successfully. Jude Kelly's fine revival of Comedians at the Lyric, Hammersmith, reminds us how well Griffiths can write at his best.

First produced in 1975, this shrewd examination of the social function of comedy (through an evening class for apprentice comics in Manchester) hasn't dated, though it's possible that English audiences are too wised-up in advance to give the drama the unpredictable reactions it thrives on. Knowing that the play is a principled scrutiny of stereotype-humour, not a mere exhibition of it, the young women sitting near me clearly had no qualms about laughing uproariously at some pretty misogynist jokes. It made for a thought-provoking but (sadly) embarrassment-free evening. Tim McInnerny, excellent in the old Jonathan Pryce part of Gethin Price, looks as Pryce would after some serious re-thinking by Gerald Scarfe. His skinhead white-face routine, where he baits two upperclass dummies ('It's not envy; it's hate'), is blood-freezing and definitely no laughing matter.

Salisbury Playhouse: 0722 320117. Lyric, Hammersmith: 081-741 2311

(Photograph omitted)