The judiciary has thus claimed not only the power to act as the final interpreter of the Constitution, but also the right, independently of the Constitution, to interpret the political system under which we live, and make all legislative acts conform to its interpretation of that system. According to this doctrine the courts are the final judges of what constitutes republican government and need not base their power to annul a legislative act on anything contained in the Constitution itself. If we accept this view of the matter, legislation must conform not only to the Constitution as interpreted by the judiciary, but to the political and ethical views of the latter as well. The President and Congress derive their authority from the Constitution, but the judiciary claims, as we have seen, a control over legislation not conferred by the Constitution itself. Yet, while laying claim to powers that would make it supreme, the judicial branch of our Federal government has, as a rule, been careful to avoid any open collision, or struggle for supremacy, with the other branches of the government. It has retained the sympathy and approval of the conservative classes by carefully guarding the rights of property and, by declining to interfere with the political discretion of Congress or the President, it has largely escaped the hostile criticism which any open and avowed attempt to thwart the plans of the dominant party would surely evoke. But in thus limiting its own authority, the Supreme Court has attempted to make a distinction between judicial and political powers which does not appear to have any very substantial basis. The essential marks of a judicial power, Judge Cooley tells us, are "that it can be exercised only in a litigated case; that its direct force is spent in determining the rights of the parties to that case; and that unless and until a case has arisen for judicial determination, it can not be invoked at all."[92] "The power given to the Supreme Court," he says, "to construe the Constitution, to enforce its provisions, to preserve its limitations, and guard its prohibitions, is not _political_ power, but is judicial power alone because it is power exercisable by that court only in the discharge of the judicial function of hearing and deciding causes in their nature cognizable by courts of law and equity."[93] In the first place it is to be observed that judicial power as thus defined is practically co-extensive with that of the legislature, since scarcely an exercise of legislative authority could be mentioned which would not affect the rights of persons or of property and which could not, therefore, be made the subject of a judicial controversy.