Lex, ordo, imperium. The communicability of legal precept in the thought of Thomas Aquinas

According to Thomas Aquinas, law is a rule or measure that moves one to act and allows to judge a conduct. Human law expresses, consequently, a general con-sideration of a rational order that, by virtue of a motion of authority, must be assumed as iudicium of her own conduct by the citizen, just as, in the virtuous act, the lower powers participate in the rational order enunciated by the judgment of prudence. This elective identity, founded on the participation of the order proper to the legal precept in the prudential imperium, makes it possible to explain in which sense law is a principle of conduct, how it is related to coercion, and how its obligatory nature is justified even when the government is imperfect.