He has died aged 80 following open-heart surgery.

Banks and his Oglala Sioux compatriot Russell Means were by the mid-1970s perhaps the best-known Native Americans since Sitting Bull and Crazy Horse, who led the attack that crushed the cavalry forces of George Armstrong Custer at the 1876 Battle of the Little Bighorn.

Banks, whose early life of poverty, alcoholism and alienation mirrored the fates of countless ancestors, led protests that caused mass disorder, shootouts, deaths and grievous injuries. He was jailed for burglary and convicted of riot and assault, and he became a fugitive for nine years. He found sanctuary in California and New York but finally gave up and was imprisoned for 14 months.

He once led a six-day takeover of the Bureau of Indian Affairs in Washington, and mounted an armed 71-day occupation of the town of Wounded Knee, South Dakota. Wounded Knee was the scene of the last major conflict of the American Indian Wars, in which 350 Lakota men, women and children were massacred by US troops in 1890.

While his protests won some government concessions and drew national attention and wide sympathy for the deplorable social and economic conditions of American Indians, Banks achieved few real improvements in the daily lives of millions of Native Americans, who live on reservations and in major cities and lag behind most fellow citizens in jobs, housing and education.

To admirers, Banks was a broad-chested champion of native pride. With dark, piercing eyes, high cheekbones, a jutting chin and long raven hair, he was a paladin who defied authority and, in an era crowded with civil rights protests, spoke for the nation's oldest minority.

To his critics, Banks was a self-promoter, grabbing headlines and becoming a darling of politically liberal Hollywood stars like Jane Fonda and Marlon Brando.

Banks and Means first won national attention for declaring a "Day of Mourning" for Native Americans on Thanksgiving Day in 1970. Their band seized the ship Mayflower II, a replica of the original in Plymouth, Massachusetts, and a televised confrontation between real Indians and costumed "Pilgrims" made the American Indian Movement leaders overnight heroes.

In 1973, after a white man killed an Indian in a saloon brawl and was charged not with murder but with involuntary manslaughter, Banks led 200 American Indian Movement protesters in a face-off with the police in Custer, South Dakota. It became a riot when the slain man's mother was beaten by officers.

"We had reached a point in history where we could not tolerate the abuse any longer, where mothers could not tolerate the mistreatment that goes on on the reservations any longer, where they could not see another Indian youngster die," he told the author Peter Matthiessen.

Weeks later, the siege that made Banks and Means famous began when 200 Oglala Lakota and A.I.M. followers with rifles and shotguns occupied Wounded Knee. About 300 United States marshals, FBI agents and other law-enforcement officials cordoned off the area touching off a 10-week battle of nerves and gunfire.

Amid wide news media coverage, the significance of the battlefield was not lost on many Americans. Dee Brown's 1970 best-selling book Bury My Heart at Wounded Knee: An Indian History of the American West had recently explored the record of massacres and atrocities against Native Americans on the expanding frontier, undermining one of the nation's fondest myths.

Proclaiming a willingness to die for their cause, Banks and Means demanded the ousting of Richard Wilson, the elected leader of the Oglala Sioux Tribal Council, whom they called a corrupt white man's stooge. The government refused. Shootings punctuated the days of stalemate, leaving wounded on both sides. Two Indians were killed, and a federal agent was shot and paralysed.

When it was over, Banks and Means were charged with assault and conspiracy. After a federal trial, with the defence raising historic and current Indian grievances, a judge dismissed the case for prosecutorial misconduct, including illegal wire taps and evidence that had been tampered with.

By then, Banks was a pre-eminent spokesman for Native Americans. He mediated armed conflicts between Indians and the authorities in various states. But his own legal troubles were not over.

Charged with riot and assault with a deadly weapon for his role in the 1973 melee in Custer, he was found guilty in 1975. Facing up to 15 years in prison, he jumped bail and fled to California.

With 1.4 million signatures on a petition supporting Banks, Governor Jerry Brown granted him asylum in 1976.

Deprived of California sanctuary when Governor Brown was succeeded by a Republican, George Deukmejian, in 1983, Banks returned to South Dakota voluntarily and was sentenced to three years in prison.

Paroled in 1985 after serving 14 months, he moved to the Pine Ridge Reservation to work as a drug addiction and alcoholism counsellor. He also turned his life around, embracing sobriety, giving talks on public service and organising cross-country events that he called Sacred Runs, which became popular among supporters of Native Americans in later years.

He is survived his wife Banks Rama and 19 children.

Robert D. McFaddenoct

New York Times