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What was the issue in Marbury v. Madison?
The justices held, through Marshall's forceful argument, that on the last issue the Constitution was "the fundamental and paramount law of the nation" and that "an act of the legislature repugnant to the constitution is void." In other words, when the Constitution--the nation's highest law--conflicts with an act of the legislature, that act is invalid. This case establishes the Supreme Court's power of judicial review.