There's more to the Fringe than laughs

Two plays aim to shock audiences by exploring the inner lives of infamous murderers. Johann Hari sees if he can learn anything about the heart of darkness

The Edinburgh Festival is a psychotic jamboree, a glorious act of collective let's-put-on-a-show lunacy. For one month a year, when the sun reaches the lukewarm peak they call "summer" in Scotland, 26,000 people flock into this gorgeous city to act out their dreams in boxes, sheds and streets, and one million people trail behind them to worship the great god Entertainment. So how better to celebrate the start of this, Edinburgh's 60th annual psychosis, than to track down two plays about real psychotics, two character studies of murderous madmen?

Terre Haute, a play by Edmund White showing at the Assembly Rooms, is a fictional coda to a real - and surreal - friendship. Timothy McVeigh was America's homegrown ultra-patriotic terrorist, a lauded-and-medalled Gulf War veteran who became convinced the United States had abandoned its constitution and become a high-tax socialist tyranny. To blast his country back to sense, he blew up 168 people (including 19 children) in the offices of the FBI in Oklahoma City. As he watched the building burn, he wore a T-shirt bearing the words of the founding father Thomas Jefferson: "The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants."

Gore Vidal is America's national gadfly, raised in Washington, DC, by his Senator grandfather. He grew up to become a confidant to Jack Kennedy, James Baldwin and Truman Capote, and his country's greatest essayist. He believes America has abandoned its republic and become an empire, its citizens imprisoned in a National Security State and forced to pay for an elephantine military that only endangers them (not least by planning and executing September 11).

From their places on the hard right and hard left, with their shared myths of a pristine lost America, McVeigh and Vidal found a strange bond, exchanging erudite letters about the death of the Great Republic. Vidal was invited to meet McVeigh and even attend his execution, but his age and health made it impossible; McVeigh died without him.

The novelist Edmund White has imagined that the meeting took place. And so we watch as McVeigh sits upright in an orange jump suit in a cage, and an elderly Vidal limps in on his stick, bristling as ever with his own brilliance. "I suppose there's something dangerous about meeting one's pen pal," he says dryly. But soon Vidal is busy reinforcing McVeigh's belief that America has become the Land of the Unfree, and projecting on to his violence his own philosophy. "Most Americans think you blew up that building out of madness or some unmotivated Iago-type evil," he says. "Nobody wants to admit you are a single outraged individual reacting to massacres at Waco, to the assassinations of Allende and Lumumba, to our wars in Kosovo, Korea, to the fact that 30 million Americans are now kept under electronic surveillance..."

The play could easily have become a brusque polemic, presenting McVeigh at his own - and Vidal's - estimation, as a misunderstood hero. But White is too subtle and supple (and sane) a writer to allow that. This alliance between a gay socialist and a survivalist neo-Nazi could never withstand an honest exchange of ideas, no matter how prepared they were to engage in mutual flattery and delusion. So the play becomes a low, slow tango, with Vidal dropping one-liners ("CNN gave me an in-depth interview about you - a whole two minutes") as the layers of McVeigh's political philosophy slowly fall away to reveal - what? A fetid core, a gnarled and perverted idealism, and an "American loneliness" that Vidal shares. "Is there anything more lonely than the angry American man driving through the West on his own, his heart bursting with indignation?" he asks his friend.

But White pays Vidal the compliment of assuming that, confronted with the reality of McVeigh's prejudices and delusions, he would have recoiled. When he hears the bomber raving about "the eight Jewish bankers who run the Federal Reserve", when he sees that his intellectual inspiration was the racist doggerel The Turner Diaries, Vidal says, "What disturbs me is how stupid I have made myself." It is a confession that the real Vidal, writing moist panegyrics to McVeigh from a thousand miles away, has never made.

But even after this concession, Vidal is still drawn to McVeigh, his judgement eroded by the tang of cordite and sex and attention. This being the work of Edmund White - the author of orgiastic gay novels - the interaction between them becomes blackly eroticised as the play progresses. At their final meeting, the militantly homophobic McVeigh bids his mentor goodbye for the last time - he will be executed in less than 24 hours - by asking what, if they were alone together, he would do to him. "I would undo the top of your jump suit and put my head on your chest," he says. "That's it?" McVeigh asks. "Yes," he says. McVeigh unbuttons his shirt and bears his chest - a moment of twisted poignancy.

As somebody who has interviewed Vidal at length, I can testify that Peter Eyre captures more than just his mannerisms in a prickly performance, measuring out Vidal's cleverness and pomposity in equal doses. But this production is badly let down by Arthur Darvill, who is not a big enough actor to fill out the contradictions of McVeigh. He does not have the hardened grizzle of a Gulf War veteran, nor the clenched fanaticism of a man trying to maintain "military decorum" as he faces execution. The tension leaks away from the show when he has to carry it. It's a shame, because this is a tender, clever play, a study of two extreme personalities meeting at the end of their lives, embarked on one final intellectual cha-cha to the grave.

The second theatrical psychopath I tracked down in Edinburgh is Ian Brady, the star - and co-author, of sorts - of Wasted at the Pleasance Dome. Forty years on from the moors murders, the image of Myra Hindley and her bleached-blonde helmet of hate has finally passed into history. The writer-director Henry Filloux-Bennett has written to Brady asking for help in understanding their torture and murder of five children, and the results make up this short play.

Brady should be a fascinating - if repugnant - subject for a drama. Here is a man who believes he intellectually reasoned himself to the point of serial-killing kids through reading the Marquis de Sade, Friedrich Nietzsche and the existentialists. He presented his crimes as a rebellion against a meaningless universe, a way of asserting the only meaningful morality - the extermination of the weak by the strong. "The crime of destroying a fellow-man is non-existent. The Chinese, the Persians, the Greeks - they all put the weak to death," he has written, providing quotes from Dostoevskyand a hundred others to prove his case.

There are all sorts of questions thrown up by this savage philosophy experiment. Which came first - the philosophy, or the sadism? Why is the Marquis de Sade celebrated as a liberatory philosopher, while his loyal disciple Ian Brady is despised? But this play avoids them all. Bizarrely, having achieved the co-operation of Ian Brady, Filloux-Bennett reduces his character to a walk-on part who offers wooden, decontextualised chunks of De Sade before wandering off again.

Instead, he focuses - insofar as the play has any focus at all - on the hoary debate about whether Myra Hindley should have been released. The play opens with Hindley on her 60th birthday addressing the audience in a northern accent so comical she resembles a serial-killer Victoria Wood. I half expected her to wheel out a piano. She makes arguments that the writer clearly thinks are very clever, but are in fact very stupid. She screams at the audience, "You have no right to judge me!" and there is a pregnant pause when we are supposed to absorb this point in quiet self-loathing. But - duh! - we do. You killed children, we didn't.

The stale familiar facts of the murders - the tapes, the trial, even a BBC newsreader recounting it all in a fraaaghtfully plummy voice - take over in a conveyor-belt of dead-handed literalism. The play is only 40 minutes long, but it feels like 40 decades as the starch-stiff cast read their cardboard lines. I would not have been surprised to emerge from the theatre and discover whole civilisations had risen and fallen in the time I spent watching this glacial show. Theodor Adorno famously said, "After Auschwitz, no poetry." Well, after Wasted, no criticism.

But that is part of the ecstasy of Edinburgh - randomly picking through the unimaginably bad on a quest for the brilliant. For the next three weeks, I will be here, sticking my snout into the trash in a quest for truffles. And as I look out over the Royal Mile, crammed with desperate performers begging to let them entertain you, I wouldn't be anywhere else.

'Terre Haute', Assembly Rooms (0131-226 2428) to 28 August, except 14 & 21; 'Wasted', Pleasance Dome (0131-556 6550), to 28 August, except 14