Thomas Silverstein, a violent white supremacist gangster who was held in isolation longer than any other American inmate in a federal prison and personified a campaign against solitary confinement as cruel and unusual punishment, died May 11 in Lakewood, Colorado. He was 67.

His death, at St. Anthony's Hospital southwest of Denver, was caused by complications of heart surgery, his wife, Renee Silverstein, said.

Silverstein had weeks ago been transferred to the hospital from a super-maximum prison in Florence, Colorado, which the federal Bureau of Prisons opened in 1994 to house terrorists, serial killers, drug lords and others considered incorrigible.