The problem in defense is how far you can go without destroying from within what you are trying to defend from without.

Eisenhower frames national defense as a moral and constitutional balancing act: a state can pursue security so aggressively—through militarization, secrecy, emergency powers, or vast expenditures—that it corrodes the very liberties, civic institutions, and economic vitality it claims to protect. The line implies that “defense” is not merely external (deterring enemies) but internal (preserving democratic character). It anticipates a recurring Cold War dilemma: how to meet real threats without normalizing permanent mobilization or allowing the instruments of security to dominate public life. The quote’s force lies in its paradox: protection can become a form of self-destruction if it undermines the society’s core values.