The powers of the Legislature are defined and limited; and that those limits may not be mistaken or forgotten, the Constitution is written. To what purpose are powers limited, and to what purpose is that limitation committed to writing, if these limits may at any time be passed by those intended to be restrained? The distinction between a government with limited and unlimited powers is abolished if those limits do not confine the persons on whom they are imposed, and if acts prohibited and acts allowed are of equal obligation. It is a proposition too plain to be contested that the Constitution controls any legislative act repugnant to it, or that the Legislature may alter the Constitution by an ordinary act.
Between these alternatives there is no middle ground. The Constitution is either a superior, paramount law, unchangeable by ordinary means, or it is on a level with ordinary legislative acts, and, like other acts, is alterable when the legislature shall please to alter it.
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.
This theory is essentially attached to a written Constitution, and is consequently to be considered by this Court as one of the fundamental principles of our society. It is not, therefore, to be lost sight of in the further consideration of this subject.
If an act of the Legislature repugnant to the Constitution is void, does it, notwithstanding its invalidity, bind the Courts and oblige them to give it effect? Or, in other words, though it be not law, does it constitute a rule as operative as if it was a law? This would be to overthrow in fact what was established in theory, and would seem, at first view, an absurdity too gross to be insisted on. It shall, however, receive a more attentive consideration.
It is emphatically the province and duty of the Judicial Department to say what the law is. Those who apply the rule to particular cases must, of necessity, expound and interpret that rule. If two laws conflict with each other, the Courts must decide on the operation of each.
So, if a law be in opposition to the Constitution, if both the law and the Constitution apply to a particular case, so that the Court must either decide that case conformably to the law, disregarding the Constitution, or conformably to the Constitution, disregarding the law, the Court must determine which of these conflicting rules governs the case. This is of the very essence of judicial duty.
If, then, the Courts are to regard the Constitution, and the Constitution is superior to any ordinary act of the Legislature, the Constitution, and not such ordinary act, must govern the case to which they both apply.
Those, then, who controvert the principle that the Constitution is to be considered in court as a paramount law are reduced to the necessity of maintaining that courts must close their eyes on the Constitution, and see only the law.
This doctrine would subvert the very foundation of all written Constitutions. It would declare that an act which, according to the principles and theory of our government, is entirely void, is yet, in practice, completely obligatory. It would declare that, if the Legislature shall do what is expressly forbidden, such act, notwithstanding the express prohibition, is in reality effectual. It would be giving to the Legislature a practical and real omnipotence with the same breath which professes to restrict their powers within narrow limits. It is prescribing limits, and declaring that those limits may be passed at pleasure.
That it thus reduces to nothing what we have deemed the greatest improvement on political institutions -- a written Constitution, would of itself be sufficient, in America where written Constitutions have been viewed with so much reverence, for rejecting the construction. But the peculiar expressions of the Constitution of the United States furnish additional arguments in favour of its rejection.