The power of the courts to refuse to apply legislative acts inconsistent with constitutional provisions has already been considered. This is as far as the courts will go in the control of the legislative department. They do not possess and have never claimed to possess the power to pass upon the credentials of one claiming membership in a legislative body. They do not attempt to regulate the rules by which such bodies are governed in the conduct of their work, and, to only a very limited extent, will they question the correctness. of the legislative records that are kept. Finally, they never attempt to command or to prohibit the performance of a legislative act. Individually, however, the members of a legislature are, of course, subject to judicial process, except so far as they have been granted express immunity by the Constitution.

Upon the other hand, as we shall see, the courts have not hesitated to protect their own independence from legislative control, not simply by refusing to give effect to retroactive declaratory statutes, or to acts attempting the revision or reversal of judicial determinations, but they have refused themselves to entertain jurisdiction in cases in which they have not been given the power to enforce their decrees by their own writs of execution. Thus, as already mentioned, they have refused to act where their decisions have been subject to legislative or administrative revisions. Finally, even where the extent of their jurisdiction, both as to parties litigant and subject-matter, has been subject to legislative control, the courts have not permitted themselves to be deprived of the power necessary for maintaining their dignity, the orderliness of their procedure, and the effectiveness of their writs.

In order that a court may perform its judicial functions with dignity and effectiveness, it is necessary that it should possess certain powers. Among these are the right to issue certain writs, called extraordinary writs, such as mandamus, injunction, certiorari, prohibition, etc., and, especially, to punish for contempt and disobedience to its orders. The possession of these powers the courts have jealously guarded, and in accordance with the constitutional doctrine of the separation and independence of the three departments of government, have held, and undoubtedly will continue to hold, invalid any attempt on the part of the legislature to deprive them by statute of any power the exercise of which they deem essential to the proper performance of their judicial functions. The extent of their jurisdiction, they argue, may be more or less within legislative control, but the possession of powers for the efficient exercise of that jurisdiction, whether statutory or constitutional, which they do possess, they cannot be deprived of.