A divided and uncertain America celebrates today the centenary of the Hollywood gunslinger who became a symbol of the nation’s once-confident swagger.

Had he not died of stomach cancer in 1979 John Wayne, the iconic screen cowboy and American patriot, would have turned 100 today to find his country beset by doubts about the Iraq war.

Thousands of fans nostalgic for his clear notion of right and wrong are expected to hold a 100th birthday bash for “The Duke” today with a rodeo show in the Iowa town of Winterset, where he was born Marion Robert Morrison on May 26, 1907.

Wayne’s son will mount a bulldozer to help to knock down an abandoned petrol station to make way for America’s first museum dedicated solely to Wayne, next to the four-room, white clapperboard house where the actor spent his first four years.

A cable television channel has been paying tribute all week by airing 35 of his approximately 170 films and a new digital 3-D version of his Hondo was shown at the Cannes Film Festival. Hollywood studios have released several collectors’ sets on DVDs.

The celebrations bear testimony to Wayne’s enduring popularity as perhaps America’s archetypal film star. He still ranks as the third-most-popular Hollywood actor behind Denzel Washington and Tom Hanks, according to a recent Harris Poll.

“The thing about Wayne is that, for better or worse, he was representing America to the rest of the world,” said Joe Leydon, a professor of film history at the University of Houston and a staff writer at Cowboys and Indians magazine.

“There have been times when that has been a good thing because there have been times in not-so-distant history when the idea of a strong, take-charge American attitude was not only respected but desired. But we live in a world now of shades of grey,” he said.

“The idea of the American can-do, take-charge, self-assured attitude is now seen as an American attitude of ‘We know what is best for you. You had better do it or else’.”

Wayne’s heroic roles, often set in the Wild West or on the battlefield, in such classics as Stagecoach (1939), Sands of Iwo Jima (1959), The Alamo (1960) and True Grit (1970) came to embody America’s self-image of rugged individualism.

“When I started I knew I was no actor, and I went to work on this Wayne thing,” he once said. “I figured I needed a gimmick, so I dreamt up the drawl, the squint and a way of moving meant to suggest that I wasn’t looking for trouble but would just as soon throw a bottle at your head as not. I practised in front of a mirror.”

While Marlon Brando won praise for his acting, Wayne earned adulation as a movie star. From 1949 to 1974 he made the Top Ten list of box-office stars on 25 occasions, including four times at No 1.

“John Wayne . . . doesn’t represent The American Man only because he was tall, rugged, straight-talking, confident and impatient. Or because the only person you could imagine having a beer with him might be General Patton,” David Hinckley, a New York Daily News columnist, observed.

“No, his real qualification, often overlooked, is that he understood that life is one long to-do list. That’s what American Men do. They live and die figuring out ways to cross items off. It’s their quintessential trait.”

The Pulp Fiction director Quentin Tarantino says that he uses Wayne’s Rio Bravo (1959) as a litmus test for potential girlfriends. Garry Wills, the Pulitzer prize-winning historian and author of John Wayne’s America, suggests that Wayne “reverses the law of optics” by looming larger the further from him we go. He describes him as “the most popular movie star ever, but also the most polarising”. Amid the cultural upheaval of the 1960s, Wayne angered many people with his outspoken support for the Vietnam War, voiced in The Green Berets (1968), which he co-directed and starred in.

The divisions created by the 1960s counter-culture persist in America, reflected in the political split between Republican “red” states and Democrat “blue” states on the electoral map.

Mick LaSalle, the film critic of the San Francisco Chronicle, argues that even though Wayne began his screen career before the Second World War he was a really a “Cold War icon”. “He first made the Top Ten list in the year that Mao took over China and the Soviets got the atomic bomb. And he stayed on top until there was a détente with the Soviets and the Vietnam War was over,” he wrote.

Robert Thompson, director of the centre for television and popular culture at Syracuse University, said Wayne was the “equivalent of Colonial Williamsburg” – the town in Virginia that has become a tourist attraction to remind Americans of their history.

“He represents the old order in a way that does not seem stodgy but somehow noble,” Mr Thompson said. “Embodied in John Wayne, the swagger had a kind of appeal. The swagger when it’s embodied in the current American attitude is perceived by the rest of the world as not appealing at all.

“It’s not perceived by most of the world as being on the side of right and justice. The swagger is still there but none of the nobility that embodied that swagger in John Wayne is there. It’s a bullying swagger.”

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