In our system of government, the Supreme Court has the authority to declare laws unconstitutional. In our nation's formative years, this authority -- the power of "judicial review" -- was seen as an essential check against the dangers of unrestrained democracy. As James Madison explained when he proposed the Bill of Rights, "independent tribunals of justice will consider themselves... the guardians of those rights; they will be an impenetrable bulwark against every assumption of power in the legislative or executive; they will be naturally led to resist every encroachment upon rights" guaranteed by the Constitution.

Alexander Hamilton added that constitutional freedoms could "be preserved in practice no other way than through the medium of the courts of justice." The "independence of the judges," he reasoned, was necessary "to guard the constitution and the rights of individuals from the effects of those ill humours which... sometimes disseminate among the people themselves." Judges, he insisted, have a duty to resist invasions of constitutional rights even if they are "instigated by the major voice of the community."

Faced with constitutional challenges to government actions, courts have two alternatives: they can uphold the law and allow it to be enforced or they can declare it invalid. When they uphold the law, they permit the majority to have their way; when they invalidate the law -- and exercise the power of judicial review -- they restrict the majority's freedom of action. The existence of judicial review matters only when the courts hold a law unconstitutional. A central question in evaluating this element of our constitutional structure is whether courts have exercised this authority wisely.

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