If the former part of the alternative be true, then a legislative act contrary to the Constitution is not law; if the latter part be true, then written constitutions are absurd attempts, on the part of the people, to limit a power in its own nature illimitable. Certainly, all those who have framed written constitutions contemplate them as forming the fundamental and paramount law of the nation, and, consequently, the theory of every such government must be, that an act of the legislature repugnant to the Constitution is void. Marshall goes on to refute the argument that the Supreme Court should concern itself only with interpreting the law, regardless of the Constitution. Then he quotes specific passages from the Constitution: It is declared that “no tax or duty shall be laid on articles exported from any state.” Suppose a duty on the export of cotton, of tobacco, or of flour; and a suit instituted to recover it. Ought judgment to be rendered in such a case? Ought the judges to close their eyes on the Constitution and only see the law?... “No person,” says the Constitution, “shall be convicted of treason, unless on the testimony of two witnesses to the same _overt_ act, or on confession in open court.” Here the language of the Constitution is addressed especially to the courts. It prescribes directly for them, a rule of evidence not to be departed from. If the legislature should change that rule and declare one witness, or a confession out of court, sufficient for conviction, must the constitutional principle yield to the legislative act? From these, and many other selections which might be made, it is apparent that the framers of the Constitution contemplated that instrument as a rule for the government of _courts_ as well as of the legislature. Why otherwise does it direct the judges to take an oath to support it? This oath certainly applies in an especial manner to their conduct in their official character. How immoral to impose it on them if they were to be used as the instruments, and the knowing instruments, for violating what they swear to support! At the end of the decision the Chief Justice concluded that the language of the Constitution confirmed and strengthened the principle essential to all written constitutions “that a law repugnant to the Constitution is void.” The Louisiana Purchase