Why did Antonin Scalia argue that capital punishment was not cruel and unusual punishment?

Antonin Scalia argued that capital punishment is not a "cruel and unusual punishment" under the Eighth Amendment based on his judicial philosophy of originalism.1

Originalism posits that the meaning of a legal text should be determined by the common understanding of its terms at the time the text was ratified. Scalia noted that when the Bill of Rights was ratified in 1791, death was a common and accepted punishment for felonies. Therefore, he reasoned that the authors of the Eighth Amendment could not have intended to prohibit a practice that was widely practiced and understood to be constitutional at that time.1

By adhering to this fixed-meaning interpretation, Scalia sought to minimize the role of the judiciary in making law, arguing that such moral and policy matters should be left to democratic processes rather than being decided by judges.1