Juridical treatments of the principle of legality are usually partial: they do not deal with all the profiles, but limit themselves to those concerning the relation between law and acts of the public administration. In order to have a comprehensive unitary vision of the same it is necessary to articulate the three fundamental meanings that it can have. First of all, it is necessary to distinguish according to whether it is invoked in the regards of the subject that claims the ultimate entitlement of political power or in the regards of subjects that exercise a derivative power. In the first case it is necessary to further distinguish whether the problem of the latitude of said power or the problem of the modalities for the exercise of such power in the regards of the members of the political group is involved. In the second case, if it is invoked in the regards of subjects that are called on to apply the laws to individual cases, the principle of legality imposes that no condition of authorised judgement must disturb the enforcement of the law on the part of the judge or administration, prescribing equal or impartial treatment. In brief, the principle of legality prescribes the governance of society through the enactment of general laws produced by a power that is not unlimited, but in turn bound by laws, and through the 'exact' enforcement of general laws.