"Our nation is founded on the principle that observance of the law is the eternal safeguard of liberty and defiance of the law is the surest road to tyranny." John F. Kennedy (1962)
Kennedy's insight is not always apparent. Many would argue that the ability to flout laws, or to do whatever one wants without constraint, is the definition of liberty. Superficially such a conception is appealing. Indeed, it appears entire swaths of our society embrace that hedonistic view of the world.
However, what America has long understood is that it is the law - adopted by the people - that protects our liberties. The Constitution - the supreme law of the land, protects liberty by dividing power among branches and limiting the authority of the government. Enforcement of the Bill of Rights is especially important to protecting the unalienable rights of individuals. Thus, paradoxically, the law is truly the great protector of liberty.
For more on the importance of the rule of law, check out Patriot Week and America's Survival Guide.