We speak of three co-ordinate branches and of their working, each in a separate and defined province; and yet, as must of necessity be the case in human affairs, the lines of demarcation are not always clear, and unless confusion is to be endless, a power must exist somewhere to determine the limits of the separate provinces, and to decide controversies in regard to them. The power to do this has been confided under the system of the United States to the courts, in accordance with the principles of the common law, if not by the express provisions of the constitution. To the United States Supreme Court is confided the duty of deciding questions involving the limitations of the different branches of the government. It diminishes the danger of collision between the different political bodies among which power is distributed, because these bodies are not brought into direct contact, but act each in its own way directly on the people; the courts regulating conflicts of authority as they arise. The peace, the prosperity, and the very existence of the Union are invested in its hands; the executive appeals to it for assistance against the encroachments of the legislative power, and the legislature demands its protection from the designs of the executive; it defends the Union from disobedience of the States, and the States from the exaggerated claims of the Union, the public interests against the interests of private citizens, and the conservative spirit of order against the fleeting innovations of democracy. This form of government, with the immense power it gives to the courts, could not exist among a people whose reverence for law and submissiveness to its mandates were not very great, and would not be possible, moreover, if it did not rest on a popular basis. CHAPTER VI. THE CANTONS.