One of the most notorious spies in U.S. history, Aldrich Ames, died on Tuesday at the age of 84.

CIA turncoat Aldrich Ames, who betrayed Western intelligence assets to the Soviet Union and Russia in one of the most damaging intelligence breaches in U.S. history, has died in a Maryland prison.

U.S. officials have long said Ames’ disclosures led directly to the arrest and execution of several intelligence sources and crippled American counterintelligence efforts during the final years of the...