Our growing softness, our increasing lack of physical fitness, is a menace to our security.

Kennedy links individual bodily vigor to national strength, arguing that a society drifting toward comfort and sedentary habits becomes less resilient in crisis. The line reflects Cold War-era anxieties: security is not only weapons and strategy, but also the population’s readiness—physically and psychologically—for sacrifice, endurance, and service. Read broadly, it is a critique of modern “softness” (overreliance on convenience, declining fitness, complacency) and a call for civic discipline. It also fits Kennedy’s wider public emphasis on youth, vigor, and public service, framing fitness as a civic duty rather than a private lifestyle choice.