Whenever a law which the judge holds to be unconstitutional is argued in a tribunal of the United States he may refuse to admit it as a rule; this power is the only one which is peculiar to the American magistrate, but it gives rise to immense political influence. Few laws can escape the searching analysis of the judicial power for any length of time, for there are few which are not prejudicial to some private interest or other, and none which may not be brought before a court of justice by the choice of parties, or by the necessity of the case. But from the time that a judge has refused to apply any given law in a case, that law loses a portion of its moral cogency. The persons to whose interests it is prejudicial learn that means exist of evading its authority, and similar suits are multiplied, until it becomes powerless. One of two alternatives must then be resorted to: the people must alter the constitution, or the legislature must repeal the law. The political power which the Americans have intrusted to their courts of justice is therefore immense, but the evils of this power are considerably diminished by the obligation which has been imposed of attacking the laws through the courts of justice alone. If the judge had been empowered to contest the laws on the ground of theoretical generalities, if he had been enabled to open an attack or to pass a censure on the legislator, he would have played a prominent part in the political sphere; and as the champion or the antagonist of a party, he would have arrayed the hostile passions of the nation in the conflict. But when a judge contests a law applied to some particular case in an obscure proceeding, the importance of his attack is concealed from the public gaze, his decision bears upon the interest of an individual, and if the law is slighted it is only collaterally. Moreover, although it is censured, it is not abolished; its moral force may be diminished, but its cogency is by no means suspended, and its final destruction can only be accomplished by the reiterated attacks of judicial functionaries. It will readily be understood that by connecting the censorship of the laws with the private interests of members of the community, and by intimately uniting the prosecution of the law with the prosecution of an individual, legislation is protected from wanton assailants, and from the daily aggressions of party spirit. The errors of the legislator are exposed whenever their evil consequences are most felt, and it is always a positive and appreciable fact which serves as the basis of a prosecution.