What did JFK mean when he said for only when your arms are sufficient beyond doubt can you be certain beyond doubt that they will never be employed?

When JFK stated that "only when your arms are sufficient beyond doubt can you be certain beyond doubt that they will never be employed," he was emphasizing the paradox of nuclear deterrence. He suggested that a strong military capability is essential for ensuring peace; if a nation is confident in its defense, it can deter potential aggression and avoid conflict. Essentially, a credible deterrent prevents war by making the costs of aggression unacceptably high for potential adversaries.