Finally, the principle that what is a "fair" or "reasonable" rate is to be measured by the customary return in private enterprises under similar conditions, has been applied in several cases to warrant the requirement of a definite rate of interest; but no precise rules have been laid down for the determination of such rate in all cases. The most striking feature, perhaps, of the development of the doctrine of judicial review here traced, as seen in the opinions of the Supreme Court, is the brevity and almost fortuitous character of the reasoning given in support of the most important and novel holdings. A comparison of the reasoning in Smyth _v._ Ames, for example, with that in Marbury _v._ Madison, in which Chief Justice Marshall first held a law of Congress unconstitutional, will forcibly exemplify this. The explanation is to be found largely in the fact that each step in advance in the building up of the doctrine had been foreshadowed in _dictum_ before it was established as decision. It was thus possible for the judge writing the opinion in a case when a new rule was actually established, to quote, as "settled law," a mere _dictum_ from a previous opinion. Justice Gray's citation, in this fashion, in the Dow case, of Chief Justice Waite's _dictum_ in the Ruggles case (although he might, with equal cogency, have cited the Chief Justice's contrary _dictum_ in the Munn or Peik cases), is a good instance of this curious use of "precedent"; and parallel instances could be adduced from virtually every one of the important subsequent cases on this subject.[22] It is apparent from this all too brief and incomplete account of the establishment of judicial review over every kind and class of state legislation affecting private property rights that no layman can easily unravel the mysterious refinements, distinctions, and logical subtleties by which the fact was finally established that property was to be free from all interference except such as might be allowed by the Supreme Court (or rather five judges of that Court) appointed by the President and Senate, thus removed as far as possible from the pressure of public sentiment. Had a bald veto power of this character been suddenly vested in any small group of persons, there can be no doubt that a political revolt would have speedily followed. But the power was built up by gradual accretions made by the Court under the stimulus of skilful counsel for private parties, and finally clothed in the majesty of settled law. It was a long time before the advocates of leveling democracy, leading an attack on corporate rights and privileges, discovered that the courts were the bulwarks of _laissez faire_ and directed their popular battalions in that direction.