reason is that, while the purpose may be to establish rights or to impose duties, they do not, in and of themselves, constitute a sufficient rule by means of which such right may be protected, or such duty enforced. In such cases, before the constitutional provision can be made effectual, supplemental legislation must be had; and the provision may be in its nature mandatory to the legislature to enact the needful legislation, though back of it there lies no authority to enforce the command. Sometimes the constitution in terms requires the legislature to enact laws on a particular subject; and here it is obvious that the requirement has only a moral force. The legislature ought to obey it; but the right intended to be given is only assured when the legislation is voluntarily enacted. Illustrations may be found in constitutional provisions requiring the legislature to provide by law uniform and just rules for the assessment and collection of taxes. These must lie dormant until the legislation is had. They do not displace the law previously in force, though the purpose may be manifest to do away with it by the legislation required. * * * * * A constitutional provision may be said to be self-executing if it supplies a sufficient rule by means of which the right given may be enjoyed and protected, or the duty imposed may be enforced; and it is not self-executing when it merely indicates principles, without laying down rules by means of which those principles may be given the force of law. Thus a constitution may very clearly require county and town government; but if it fails to indicate its range, and to provide proper machinery, it is not in this particular self-executing, and legislation is essential. Rights in such a case may lie dormant until statutes shall provide for them, though, in so far as any distinct provision is made which by itself is capable of enforcement, it is law, and all supplementary legislation must be in harmony with it." Cooley on Principles of Constitutional Law, speaking of the thirteenth amendment to the federal constitution, prohibiting slavery and involuntary servitude, says, on page 219: "The same amendment also provides that 'congress shall have power to enforce this article by appropriate legislation.' Whether this provision has any importance must depend upon whether the prohibitory
