No people in history have preserved their freedom who thought that by not being strong enough to protect themselves they might prove inoffensive to their enemies.

Dean Acheson (1893–1971) American statesman

National Security Council Report 68 (NSC-68), Sec. 7 “Present Risks” (14 Apr 1950) [with Paul Nitze]
    (Source)

Usually paraphrased as "No people in history have ever survived who thought they could protect their freedom by making themselves inoffensive to their enemies."