"Although covert political action became an important tool of US policy America never completely abandoned its moral traditions. The threat of international Communism, however, became a compelling rationale for covert action, to the extent that many operations needed no more specific justification. Thus the Cold War, and the perceived severity of the Soviet threat, made it possible for policymakers to ignore competing ethical considerations when they endorsed covert actions."
Center for the Study of Intelligence: https://www.cia.gov/library/center-for-the-study-of-intelligence/index.html
Studies in Intelligence (1992), v.36 no.5