This paper aims to explore two objections raised against Bulygin’s second approach to the definition of the nature of legal power-conferring rules. According to the first objection, such an account is vague about what is defined by legal power-conferring rules qua constitutive rules. I maintain that this vagueness is rooted in the lack of a suitable definition of legal power. I shall be arguing for the reduction of the complexity of the definientia by defining legal power as a species of (...) competence. According to the second objection, this non-reductive approach cannot explain the normativity of this kind of rules. Against this approach, it argues that legal powerconferring rules perform a deontic and a definitional function as constitutive rules of legal practice. (shrink)