AIM’s growing prestige and influence, however, threatened the conservative Sioux tribal chairman, Dick Wilson. When Wilson learned of a planned AIM protest against his administration at Pine Ridge, he retreated to tribal headquarters where he was under the protection of federal marshals and Bureau of Indian Affairs police. Rather than confront the police in Pine Ridge, some 200 AIM members and their supporters decided to occupy the symbolically significant hamlet of Wounded Knee, site of the 1890 massacre. Wilson, with the backing of the federal government, responded by besieging Wounded Knee.
During the 71 days of the siege, which began on February 27, 1973, federal officers and AIM members exchanged gunfire almost nightly. Hundreds of arrests were made, and two Native Americans were killed and a federal marshal was permanently paralyzed by a bullet wound. The leaders of AIM finally surrendered on May 8 after a negotiated settlement was reached. In a subsequent trial, the judge ordered their acquittal because of evidence that the FBI had manipulated key witnesses. AIM emerged victorious and succeeded in shining a national spotlight on the problems of modern Native Americans.