Clint's not a cowboy after all

"The fellows in this film [which features Jamie Bell] were just skinny kids out of the Depression," he continues. "The average age on that island was 19. They got into it because they had to join something or because they were drafted. When I was drafted during the Korean War in 1951, people weren't volunteering so much - and as every war has progressed through to now, there's not a lot of people who would.

"Nobody really wants to be involved in fighting and you can see why they feel that way. You've got the United Nations claimingit is going to solve things but it doesn't do much. It's a tough time for citizens to work out what it all adds up to. To fight, you have to feel like there is an end to it, but history doesn't allow us to think that."

About half the film takes place on Iwo Jima itself, the desolate Pacific island of black sand and sulphurous caves, where more than 6,800 US troops lost their lives in early 1945. And if the film doesn't give a single insight into the 22,000 Japanese who also died there, that is because Eastwood was concurrently shooting another film from their viewpoint called Letters From Iwo Jima which opens in Japan in December.

Shot in Japanese and starring Ken Watanabe as General Tadamichi Kuribayashi, it is the ultimate humanitarian statement by Eastwood on the senseless killing of young men, regardless of flag.

"As I researched the stories of the American Marine Corps on Iwo Jima, I started to come across the brilliant strategies of the Japanese general who commanded the island," says the director. "It turns out that Kuribayashi was an envoy to the US in the 1920s and liked America. He thought it ill-advised that the Japanese empire would go to war with America. I started to wonder how a person like that defended the island and turned what they thought was going to be a three- or four-day battle into a month of absolute mayhem."

Eastwood read the general's letters to his family from Iwo Jima and then travelled to Japan to meet the Iwo Jima Association, a group of Japanese veterans. "None of them were actually on the island, because the Japanese suffered almost total casualties. There was nobody around to tell what happened to these characters, but their letters home showed that they had the same desires and concerns that the men on our side had. Between the two movies, I think it sums up into a statement that war is a futile exercise at best."

Even though Flags of Our Fathers is so liberal in perspective, it's still a surprise to hear the Republican Eastwood expressing such Left-leaning views. Born in 1930, to itinerant workers in Depression-era California, his beginnings were humble: a working-class kid who worked as a lumberjack, a swimming instructor and a piano player before getting into acting in 1954.

Unlike most Hollywood players, who favour the Democratic Party, Eastwood was always a Republican. He openly supported Richard Nixon in the 1968 and 1972 elections and attended Nixon's reelection celebrations two years before the Watergate scandal broke alongside his staunchly Right-wing buddies John Wayne and Charlton Heston.

In 1986, frustrated at the red tape he encountered over a planning application in his home town of Carmel in northern California, he decided to run for mayor on the Republican ticket. After a discreet and exclusively local campaign, he won 72 per cent of the vote and served for two years. During that time, he managed to save some beautiful local land from developers, while also ensuring that some building went ahead, including a new children's library and a tourist parking lot.

But Eastwood was starting to stray from the party. He defended his close friendship with Ronald Reagan not by voicing his support for Reagan's policies but arguing that he would befriend any president in order to make his concerns about the environment heard. In 1992 he refused to support George Bush's electoral campaign, later publicly announcing that he had voted for a "third-party" candidate, the independent Ross Perot.

It was probably his marriage in 1996 to Dina Ruiz, a woman of European and African-American extraction who was raised by a Latin couple in California, that finally sealed Eastwood's political transformation. The two had a daughter,

Morgan, the year they married and have lived together happily for a decade. Eastwood's politics can't help but have been affected in that time by a wife who identifies herself as a Latina, since the huge and increasingly powerful Latin population in the US has always tended towards the Left.

He now describes himself as libertarian and several of his more recent films - Midnight in the Garden of Good and Evil (1997) with its gay and transvestite characters and critical picture of entrenched Southern society, and Million Dollar Baby (2004) with its sympathetic portrayal of euthanasia - have alienated him from the hard-Right conservatives.

His career has echoed his changing outlook. Early on, as an actor, he specialised in tough anti-heroes with an individualist streak, from his breakthrough as The Man With No Name ("everybody gets rich or dead") in Sergio Leone's classic spaghetti western trilogy of the mid-1960s, to Dirty Harry, the maverick cop of the 1970s who always chose extreme violence over procedure.

It was only in the 1980s, as his directing career took off, that Eastwood got to explore his true interests: the foibles and failings of human behaviour, especially the inability of men to communicate.

Bird (1988) was an intense three-hour portrait of Charlie Parker, the jazz legend, and his battle with drugs and booze. His anti-western Unforgiven (1992), in which he also starred, a devastating portrait of the evil that men do, won him two Oscars. And who can forget the painfully tender love story The Bridges of Madison County in 1995, one of the most mature, heartbreaking love stories of that decade.

In recent years, the septuagenarian director has hit a dazzling stride. Mystic River (2003, two Oscar nominations); Million Dollar Baby, the following year (two Oscars). He remains on form with the compelling, grisly yet beautifully cinematic Flags of Our Fathers.

He doesn't seem worried that some won't be eager to support the new film, which opens in America this month. In the end, all that seems to matter is that he has made a movie he believes in.

"I am not a person to get on a soapbox, but if you don't pay attention to history, you are destined to relive it. It doesn't seem like we do pay attention to our past and maybe through making these movies I can make some statement about it."

Flags of Our Fathers is released on 22 December.