INTERCESSIO. - In Roman public law the i. begins with the founding of the Republic, and at first means the right of one of the consuls to prevent, by virtue of the par potestas, an act performed by the other consul from producing legal consequences.
The concept of i. is intimately linked to that of collegiality. When, subsequently, new magistracies were created, the right of i. was held not only between colleagues, but the superior magistrate, by virtue of his maior potestas, could with the i. intervene against measures taken by the inferior magistrate. The consul could therefore intercede against the acts of every other magistrate, and the praetor could do likewise with regard to the magistrates inferior to him: however, while the major magistrates could intercede against those holding a high rank in the cursus honorum, and against the minor magistrates, among the latter, though hierarchically ordered, the i. did not take place. The censor then had a particular position, since he could not oppose, and against whom the i. could not be opposed.
To these limitations of powers that exist between magistrates, there is then added, with the institution of the tribunes of the plebs in 487, another i., which is in fact the most frequently used. The tribunes of the plebs are not magistrates, but, provided with the right of auxilium, in defense of the interests of the plebs, they can intercede against the acts of any magistrate (except of course the dictator), against the provisions of senatusconsulta, against the rogationes presented to the vote of the comitia. And this i. of the tribunes is the one that had the widest application. It is understood, however, that such a right could be exercised only within the city and its immediate surroundings. Therefore the acts performed by a magistrate provided with imperium to be exercised outside the pomerium are exempt from i.
In the Empire the right of i. belongs first of all to the emperor by virtue of his tribunicia potestas, and it belongs to him in a broader form than before, not only because the tribunicia potestas ended up becoming a power for life, but also because it was valid not for the city of Rome alone, but for the whole Empire, and could not be countered by the i. of another tribune of the plebs, there being no collegiality between the tribune of the plebs and the princeps invested with the tribunicia potestas. In the 1st century of the Empire there is record of cases of i. by the emperor, and even, much more rarely, of tribunes of the plebs against acts of magistrates; then the one i. remains crushed, the other becomes superfluous with the affirmation of imperial absolutism.
Bibliography3 works
Roberto Paribeni