In the 1991 case Keith J. Hudson v. Jack McMillian, et al., the U.S. Supreme Court ruled in favor of a Louisiana prison inmate who alleged that he had been subjected to cruel and unusual punishment, which is prohibited by the Eighth Amendment of the Constitution. The plaintiff, Keith J. Hudson, claimed that he was beaten by two prison guards while another watched and did nothing to stop it; all three were sued for damages under Section 1983 Title 42 of the United States Code (a civil rights statute). The defendants argued they should be immune from liability because no significant injury occurred as a result of their actions - an argument initially accepted by lower courts on appeal from district court's decision in favor of Hudson. However, upon reaching Supreme Court level review with Justice Sandra Day O'Connor delivering majority opinion joined by five other justices including Chief Justice William Rehnquist; it was held that use of excessive physical force against prisoners could constitute cruel and unusual punishment even if prisoner does not suffer serious or significant injuries thereby reversing previous rulings.

In the dissenting opinion for Keith J. Hudson v. Jack McMillian, Justice Thomas, joined by Justice Scalia, argued that while they did not condone the use of excessive force against prisoners, they believed this case should be dismissed because it failed to meet a standard established in previous cases requiring proof of "significant injury." They contended that Hudson's injuries were minor and thus did not constitute cruel and unusual punishment under the Eighth Amendment. The justices also expressed concern about federal courts becoming involved in micromanaging state prisons through lawsuits over minor incidents of alleged misconduct by prison officials. They suggested such matters would be better handled internally within prison systems or at most through state courts.