The legitimization of the law is usually based on a philosophical interpretation of legal and political practice and serves to bring rationality, reasonableness to this practice. Where the content of the law is given in the form of legal regulations and the dispute concerns syntactic elements of a rule of conduct, such dispute falls within the scope of interpretation of the law. Therefore, a dispute as to the content of legal regulations that concerns the Constitutional Tribunal does not, as a rule, fall within the scope of legitimacy of the law. Such a dispute is settled by the use of certain directives of interpretation of the law, which requires determining which of them apply in a given situation. Such legitimacy can be called the legitimacy of directives of legal interpretation, or the legitimacy of interpretation of the law. It requires the definition of criteria for the validity of directives on legal interpretation.