The bedrock upon which the American political system is built is the rule of law.

Rule of Law: In some cases this will be clearer than others, but basically you want to identify the principle of law on which the judge or justice is basing the resolution of the case. This is what you’ll often hear called “black letter law.”

The cases on the subject are collected in a footnote to Somerset Bank v. Edmund, 10 Am. & Eng. Ann. Cas. 726; 76 Ohio St. Rep. 396, the head-note to which reads: "Public policy and sound morals alike forbid that a public officer should demand or receive for services performed by him in the discharge of official duty any other or further remuneration or reward than that prescribed or allowed by law." This rule of public policy has been relaxed only in those instances where the legislature for sufficient public reason has seen fit by statute to extend the stimulus of a reward to the public without distinction, as in the case of United States v. Matthews, 173 U.S. 381, where the attorney-general, under an act for "the detection and prosecution of crimes against the United States," made a public offer of reward sufficiently liberal and generic to comprehend the services of a federal deputy marshal. Exceptions of that character upon familiar principles serve to emphasize the correctness of the rule, as one based upon sound public policy.