Early on in Michael Clayton, there's a moment of metaphorical genius when we meet Karen Crowder, one of the bent lawyers who populate this impressive legal drama. Slumped in a lavatory stall at U/North - the agrochemical company facing a multimillion-dollar class action suit at which she is chief consul - Crowder pulls herself to a nearby washbasin and looks up. 'Which is the thing we always ask about these people,' says Tilda Swinton, who plays Crowder.
'How do they face themselves in the mirror in the bathroom every morning?'
Crowder isn't the only one having to come to terms with herself in the film. Played by George Clooney in less-than-gorgeous mode, Michael Clayton is an in-house fixer for Manhattan corporate law firm Kenner, Bach & Ledeen, meaning he toils behind the scenes cleaning up clients' messes in a life of perpetual damage limitation. This, along with mounting debts from an out-of-control gambling habit and a failed business venture, means the divorced Clayton is already an empty husk of a man when we meet him. By the time he becomes embroiled in the U/North case, he must join Crowder, looking in that mirror at an ugly reflection.
Debut director Tony Gilroy, best known for his work writing The Bourne Identity and its two sequels, first thought about writing Michael Clayton when he was researching his 1997 script for Taylor Hackford's The Devil's Advocate. Frequently meeting with lawyers as he sketched the character of Clayton, he says his protagonist remains a composite. 'I've never met anybody who does exactly what Michael Clayton does. It's not exactly something a law firm goes out and advertises,' he says.
And although the film is inspired by real lawsuits, such as the infamous Anderson versus General Motors case in the 1970s, he sounds a note of caution. 'I'm wary of making the movie issue-based.'
Swinton also met lawyers in preparation for her role. 'I realised that world exists and that it's as opaque and hallucinogenic as it looks,' she says. 'They speak a language that I don't even think they understand. And a lot of them are obsessed with shoes and all sorts of other things.'
Yet she evidently has sympathy for Crowder. 'She's trying to be the good girl that she always intended to be. She's a soldier. That's the way I think of her. She's signed up to an ethos and she's signed up to a particular corporation. She's signed up to a way of being, in quite a soldierly way. She's determined not to ask for help. She talks at the beginning, in the electronic press kit she's doing for U/North, about the sense of pride in having this job and being able to draw on your own resources.'
When it came to casting Clayton, Gilroy felt Clooney was perfect. 'With George what you got was a guy who maybe had skated on his looks and all this early promise,' he says, with a wry smile.
With bags under his bleary eyes, Clooney's Clayton looks suitably washed out. After completing his own directorial effort, Good Night, and Good Luck, Syriana, in which he injured his back, and The Good German, he was exhausted. It didn't help that he went on to campaign for the 2006 Oscars - in which he eventually won best supporting actor for Syriana.
'I was really beat up,' says Clooney. 'I still was a little heavy as I couldn't exercise because of this injury, but I thought that was probably a good thing too - to be out of shape and not feel good.'
Clayton is one of the most repellent legal eagles since Paul Newman's booze-sodden ambulance chaser Frank Galvin from Sidney Lumet's 1982 classic The Verdict. Clooney watched Newman's turn in preparation for the role, although you could just as easily compare Clayton with some of the disillusioned anti-heroes of 1970s Hollywood films such as Network, The Parallax View and All the President's Men. 'If you put this movie down in 1978, it would probably seem part of the fabric,' Gilroy says.
The difference now, says Clooney, is that studios 'don't want to make those films any more. Something like Michael Clayton simply isn't a commercial film.'
It's a sad reflection of audience tastes in the multiplex age, compared with the 1970s, when politically charged films drew in the crowds. Clooney considers himself 'the bodyguard' for such projects.
'It's my job to get those films made - or be bored,' he says. 'The good thing is that there are a lot of places you can go to find money, if you're willing to do it for nothing, which is what I do with films. You gamble on the film making money. If it makes money, you make a living. The Good German and Solaris didn't make any money. With a lot of films, you don't make any money off them, but you do them because you want to make the films.'
Yet Gilroy says Clooney isn't quite the saviour of cinema he might have us believe he is. After Gilroy had written the script, he showed it to Clooney's former creative partner, Steven Soderbergh, who was enthusiastic and thought they should make it on a low budget on digital video, with the actor playing Clayton.
'We went to George and he said, 'I don't want to meet him. I don't want to work with a first-time director. I don't want to have anything to do with it',' says Gilroy.
Clooney tells it a little differently. 'I'm a little cautious with first-time directors obviously,' he says. 'But when you meet Tony, the minute he walks into the room, you go, 'I trust this guy'.'
However, it took Gilroy a further two years - raising the money without Clooney's help - before he was able to walk in that room. He had decided that he needed to at least talk to the actor before looking elsewhere for a male lead. 'I just started bothering everybody and it took me about three weeks to bug my way into his house. And we got a movie out of it. It was a good meeting,' he says.
'It was an all-day thing. I went to his house on a Sunday morning. I had no idea how long the meeting would last, and for 11 hours, with no food - he never fed me! - we sat and talked,' Gilroy recalls.
However torturous its birth, there's no doubt Michael Clayton is one of the most important American films this year. Just as 1970s US cinema recognised social disillusionment, its pessimistic post-9/11 world-view represents a growing mood of discontent in the country.
'It's been a very dark period in America,' says Gilroy. 'September 11 wasn't just good for Osama bin Laden, was it? It had a lot of other consequences. People are lost.'
Swinton calls the film 'Hollywood dark' and credits it with political integrity. Whether it sways audiences remains to be seen but one thing's for sure: it's in line for recognition at next year's Oscars, Clooney and company are unlikely to get much rest.
Michael Clayton is screening now