Stephen Gaghan spent two years and logged thousands of miles researching Syriana, a twisty, challenging - and deliberately ambivalent - depiction of power games in the Middle East. The Oscar-winning writer sounds off to Hugh Linehan about big oil, dumb journalists and his own jihad against Hollywood cowardice. Just don't say the word 'confusing'

'YOU have to have a hero who wears a white hat, who's usually a white person. That's the good guy. And then there's a bad guy foaming at the mouth, a wide-eyed brown-skinned person with his hand on the plunger. The degree that you want to move away from that formula dictates how difficult it will be to make your movie."

Coiled up in a chair in a London hotel, Stephen Gaghan is describing the pitfalls of trying to break the pre-determined mould of the Hollywood genre movie. In the writer-director's new film, Syriana, there are no white hats. Everything is in shades of grey. Set in locations ranging from Tehran and the Persian Gulf to Beirut, Spain, Switzerland, Texas and Washington, DC, this multi-layered, densely plotted portrait of the web of intelligence, counter-intelligence, terrorism, counter-terrorism, corruption and money which binds together the opposing factions involved in the Middle Eastern oil industry offers many questions but few answers.

A world-weary CIA agent (George Clooney) fears he is being thrown to the wolves by his superior officers; a Geneva-based financial analyst (Matt Damon) becomes embroiled in the succession struggle in a Gulf state; a powerful Texas oil company faces corruption charges over a contract in Kazakhstan; an impoverished young Pakistani immigrant labourer is thrown out of work and finds comfort in a madrassa which preaches jihad against the West. And in the background, shadowy forces pull strings and manipulate outcomes.

Although Syriana has been widely praised, and picked up a couple of Oscar nominations (for Clooney's performance and Gaghan's script), the film-maker is incandescent with anger about American journalists who have branded the film too complicated and confusing to reach a mass audience.

"They're all asking: 'Who are we rooting for? Who do we want to see succeed at the end? It's too confusing!' And the point is, it's not confusing. These storylines have beginnings and middles and ends. They're simple. What the film does is it challenges the way you watch movies like this. It doesn't tell you who's the star of the scene. It's shot to purposely challenge your assumptions of how you watch a film like this."

And besides, film journalists just aren't equipped for the task. "They can't talk about the issues in the film because they don't know enough, about Washington, about the Middle East, about foreign policy, about the oil business, lawyers . . . They don't know anything about any of that. They only thing they can talk about in the US is that the movie's too confusing for the middle of the country. They become these self-appointed protectors of the poor little lambs, the great unwashed. Well, I'm from Kentucky and I am one of the great unwashed."

Actually, today he looks pretty clean, if a bit dishevelled. But then, the 40-year-old Gaghan is a rather different species from the usual smooth operators who come through the doors to tell you what a great movie they've made. He peppers the conversation with imitations of venal studio executives and dumb journalists; he's disarmingly frank about what he was prevented from doing on Syriana. You get the impression that, given enough time, he'd spill the beans on pretty much anything. He is, frankly, wired.

A confessed obsessive-compulsive who kicked his drug problems in his early 20s before publishing some short fiction and working for the Paris Review, Gaghan had a brief but successful stint writing TV drama for series such as The Practice and NYPD Blue, which propelled him into writing for the big screen, although it doesn't seem to have brought him happiness.

"I am so incensed by the shortcomings of it all," he says. "I'm just in a constant fog of depression about it, which is very motivational. People ask: 'Aren't you happy? Aren't you proud of your Academy Award nomination? Don't you feel good?' No, no. I don't feel good about it. I feel bad. And it's not false humility. I'm wired for self-criticism, and that's the way I am. I want to do way better. So I get up in the morning, chewing myself up inside, saying what have I learned? How did I fail? What can I do? I want to make the system work for me, and have it projected all over the world."

Gaghan describes the media reaction to Syriana as hugely frustrating and disappointing. "You spend 15 hours a day, seven days a week, for four years, and all that people can think to say about your work is 'Don't you think it's too confusing?' No, I don't. I'm sorry Michael Douglas doesn't save his daughter, that there isn't a sentimental heartbeat at the core of this, but that's not what the world dictates right now."

That dismissive reference to Michael Douglas saving his daughter harks back to Traffic, the screenplay which made Gaghan's name, won him an Oscar and provided him with the clout to spend two years travelling the world on Warner Brothers' tab while researching Syriana. Directed by Steven Soderbergh, Traffic was another panoramic portrait of a multi-billion dollar industry, illegal narcotics. Gaghan readily agrees that it was because of that film's success that he was able to embark upon Syriana."It's because of Traffic that this was even remotely possible," he says. "No Traffic, no Syriana. They'd never have taken the risk of something like this. I wanted complexity, and studios and producers resist complexity, whether it's Warner Brothers or anyone else."

Given all this, I express my surprise that he was the credited screenwriter on Rules of Engagement, a repellent military courtroom drama in which Samuel Jackson plays a US Army officer accused of massacring unarmed rioters outside the US embassy in Yemen. In that film's final act, it is revealed in flashback that Jackson was right all along, that the rioters were actually armed to the teeth with RPGs and machine guns, and that the killings were justified. It's as if somebody had made a Boys' Own action adventure about Bloody Sunday, based on the Widgery report, with the paras as the heroes.

"It wasn't in the original script," responds Gaghan. "It was designed to be Paths of Glory [Stanley Kubrick's 1957 film about a court-martial in the French army during the first World War]. That's what I worked on. At the end of the day Sam Jackson was guilty. He did have a racist streak and he did snap and he did shoot those people.

"In the inimitable style of Hollywood, after the film was shot and put together and tested, I got a phone call from the head of the studio. It started out like this." He puts on a high-pitched, insincere schmoozing voice. "'Sweetie, I've got good news! People love Sam! He's testing through the roof!' The hair's standing up on the back of my neck like an animal. What do you mean? 'Well, people love him, and he can't be guilty.'

"I've been working for a year and a half straight predicated on one idea, that he's guilty. The only thing you could do to wreck that movie is make him innocent. So I quit, and they started faxing me pages, 'written by military adviser Dale Dye'.

"Trust me, the exact same shit went on with this movie. I'm not going to get into it, but the same forces of over-simplification, explanation . . . there are parts of Syriana where you go to the CIA and they just start explaining shit. You should never do that in a script. Never, never, never. A movie should operate on certain principles, but principles and money? It's a fucking joke."

Surely, though, the entire history of cinema tells us that it's always been a collision between principle and expediency, and that, in order to make films such as Syriana, you have to make compromises and be realistic about what you can achieve?

"That's exactly right, and to get the opportunity to do it, and the resources and the expertise, to bring all these people together, you're dealing with a giant banking and distribution entity. All power to Warner Brothers for having the courage to even go down this road. What a strange undertaking. They can spend their whole lives doing Batman and Superman and Harry Potter. They didn't need to bother with this. This was a huge pain in the ass for everyone involved."

The title Syriana comes from a term used by Washington think-tanks to describe a hypothetical reshaping of the Middle East. According to Gaghan, he is using it more abstractly, to refer to the "fallacious dream that you can successfully re-make nation states in your own image". So, despite the absence of clear-cut heroes and villains, he clearly does hold a strong view on the current US project of regime change in the region.

"But it's hard-earned," he argues. "I didn't start out with that perspective or with a pre-existing bias. I just went around and talked to as many people involved in the drama as I could, from the Arab side to the Washington, DC side. I talked to the families that own oil-producing countries and I talked to the middlemen in Europe and the people in American oil companies. I just went around and asked all these questions."

Along the way, he met everyone from neo-con intellectual Richard Perle to the leader of Hizbullah in Beirut, along with oilmen, financial analysts and arms dealers.

"Certain themes emerged, and my worldview shifted a little bit. What I thought about how it all worked changed. I became much more tolerant of the people involved. They were better people than I expected. When you talk to people they become humanised, and they're not the cardboard cutouts you expected or that you've reduced them to. But the level to which greed and a very narrow form of self-interest motivated the players in the drama - I was very surprised by that. There's much less altruism and much more 'I'm going to get mine now'. And that was really everybody."

One of the things that struck Gaghan most, and which comes across in the film, was how small and interlinked the world of power and influence in the oil industry is.

"They're just like puppies all on top of each other in the basket. It's like one living organism.You pull at a strand here and they feel it over there. The world of these people who wield influence is actually quite small, a handful. It's a thousand people, and they all know each other."

Which, I suggest, is grist to the mill of conspiracy theorists from both left and right. "Yeah, but I take a very strong stand on that in Syriana, which is that nobody's that good. Nobody could pull off a conspiracy, and keep it secret. They're all just going for their own very narrow, limited self-gain.

"And the result of that sometimes is to drive the car off the cliff, but it's from a whole series of individual decisions that you can never predict. There's no computer model you could build that would make it work this way. Dick Cheney's over there, thinking in the back of his mind about Haliburton stock prices and all his friends, and he's got his point of view, and over there you've got Rumsfeld fighting for his turf, and so on."

But the overriding impression one gets from Syriana is of a system of power which has been in place since the end of the second World War at least, but is beginning to collapse under the pressure of economic imperatives, political violence and global change.

"Exactly," says Gaghan, rather gleefully. "I think you can feel it coming, can't you? We've reached peak oil production, and the carbon economy's going to change. You have this incredible fact that China has 10 million cars now and in 20 years they're going to have 100 million cars. India's on the same trajectory. What does that mean for oil prices? They're not going to be within reach of the average person. There'll be giant structural shifts. I think it's exciting - and terrifying."

And underlying it all is the suicide bomber, intent on destroying the whole edifice.

"It's the deus ex machina. It's the random thing you can't predict. You're Talleyrand and you have your master plan for how you're going to order the world, and it all makes perfect sense. And then it doesn't, because somewhere there's some kid you can never predict or protect yourself against because he's willing to give up his life. Suddenly the whole system, all your life and all your plans, are vulnerable because of this crazy act.

"That's the entropy, that's the cancer, that's the wild card. It never works out the way you plan. That's the hilarious fallacy of empire-building."

Syriana is showing tomorrow at the Jameson Dublin International Film Festival, and is released on March 3rd