You can have peace. Or you can have freedom. Don't ever count on having both at once.

The line frames a stark trade-off between social tranquility (“peace”) and individual or political autonomy (“freedom”). It suggests that maintaining freedom entails friction—conflict, risk, and the need for vigilance—while peace often requires conformity, restraint, or the surrender of liberties to authority. In Heinlein’s recurring political imagination, stable order can shade into coercion, and liberty can be noisy, dangerous, and costly. The aphorism functions less as a universal law than as a warning: if a society promises perfect security and calm, it may be doing so by limiting choice and dissent. Conversely, a free society should expect contention and uncertainty as the price of self-determination.