Justice Harlan's opinion is interesting not only because it touches upon the possibility of a _judicial_ review of the rate fixed by the legislature; but because the learned Justice bases his contention on the _contract_ between the railroad and the state to the effect that rates should be "reasonable." This indicates plainly that not even in the mind of Justice Harlan, who later became the firm exponent of the power of judicial review, was there any clear belief that the Fourteenth Amendment as such gave the Court any power to review the "reasonableness" of a rate fixed by the legislature. In other words, he derived his doctrine of judicial review from the power of the Federal judiciary to enforce the obligation of contracts, and not from its power to compel "due process of law." It is impossible to trace here the numerous decisions following the Ruggles case in which the Supreme Court was called upon to consider the power of state legislatures to control and regulate corporations, particularly railways. It is impossible also to follow out all of the fine and subtle distinctions by which the _dictum_ of Chief Justice Waite, in the Munn case, to the effect that private parties must appeal to the people, and not to the courts, for protection against state legislatures, was supplanted by the firm interpretation of the Fourteenth Amendment in such a manner as to confer upon the courts the final power to review all state legislation regulating the use of property and labor. Of course we do not have, in fact, this clear-cut reversal of opinion by the Court, but rather a slow working out of the doctrine of judicial review as opposed to an implication that the Court could not grant to corporations the relief from legislative interference which they sought. There are but few clear-cut reversals in law; but the political effect of the Court's decisions has been none the less clear and positive. _The Minnesota Rate Case_ It seems desirable, however, to indicate some of the leading steps by which the Court moved from the doctrine of non-interference with state legislatures to the doctrine that it is charged with the high duty of reviewing all and every kind of economic legislation by the states. One of the leading cases in this momentous transition is that of the Chicago, Milwaukee, and St. Paul Railway Company _v._ Minnesota, decided in 1889, which made a heavy contribution to the doctrine of judicial review of questions of political economy as well as law. This case involved the validity of a Minnesota law which conferred upon a state railway commission the power to fix "reasonable" rates. The commission, acting under this authority, had fixed a rate on the transportation of milk between two points.