The real kernel of the tribune's power consisted in his intercessio, or right of invalidating ordinances, whether framed by the senate or proposed by a magistrate to the comitia, or issued by a magistrate in pursuance of his office. From 367 B.C. down to the time of the Gracchi the power of veto in public matters was, on the whole, used in the interests of the gov erning families to check opposition arising in their own ranks. A recalcitrant consul was most readily brought to obedience by an exercise of tribunician power. The tribunes found a field for con stant activity in watching the administration of justice, and in rendering assistance to those who had received harsh treatment from the magistrates. The tribunes were, in fact, primarily legal functionaries, and constituted in a way a court of appeal. It was to this end that they were forbidden to pass a whole night away from the city, except during the Latin festival on the Alban Mount, and that they were expected to keep their doors open to suppliants by night as well as by day. They held court by day in the Forum and frequently made elaborate legal inquiries into cases where their help was sought. We hear of this not infrequently in Cicero's speeches, and in other writings which deal with legal matters. According to the general principle of the constitution, magistrates could forbid the acts of magistrates equal to or in ferior to themselves. For this purpose, the tribunes were deemed superior to all other officers. If a tribune exercised his veto no other tribune could annul it, for the veto could not be itself vetoed, but it was possible for another tribune to protect a definite individual from the consequences of disobedience. The number of the tribunes made it always possible that one might baulk the action of another, except at times when popular feeling was strongly roused. The veto was not, however, absolute in all direc tions. In some it was limited by statute ; thus, the law passed by Gaius Gracchus about the consular provinces did not permit a tribune to veto the annual decree of the senate concerning them. When there was a dictator at the head of the state, the veto was of no avail against him. One of the important political functions of the tribunes was to conduct prosecutions of state offenders, particularly ex-magistrates. These prosecutions began with a sen tence pronounced by the tribune upon the culprit; whereupon, exercising the right given him by the XII. Tables, the culprit appealed. If the tribune sought to inflict punishment on the cul prit's person, the appeal was to the assembly of the centuries ; if he wished for a fine, the appeal was to the assembly of the tribes.
It is commonly stated that a great change passed over the tribunate at the time of the Gracchi, and that from their day to the end of the republic it was used as an instrument for setting on foot political agitation and for inducing revolutionary changes. This view is an inversion of the facts. The tribunate did not create the agitation and the rev olutions, but these found vent through the tribunate, which gave to the democratic leaders the hope that acknowledged evils might be cured by constitutional means, and in the desperate struggle to realize it the best democratic tribunes strained the powers of their office to their ruin. For the bad tribunes did not hesitate to use for bad ends the powers which had been strained in the attempt to secure what was good. But the tribunate only fared like all other parts of the republican constitution in its last period. The consuls and the senate were at least as guilty as the tribunes. After a severe restriction of its powers by Sulla and a restoration by Pompeius, which gave a twenty years' respite, the essential force of the tribunate was merged in the imperial constitution, of which indeed it became the principal constituent on the civil side. The ten tribunes remained, with very restricted functions. The emperors did not become tribunes, but took up into their privi :eges the essence of the office, the "tribunician authority" (tribu nicia potestas). This distinction between the principle of the office and the actual tenure of the office was a creation of the late republic. Pompeius, for example, when he went to the east, was not made proconsul of all the eastern provinces, but he exercised in them a "proconsular authority," which was the germ of the imperial authority on its military side. Similarly the emperor, as civil governor, without being tribune, exercised powers of like quality with the powers of the tribune, though of superior force. By virtue of his tribunitian authority he acquired a veto on legis lation, became the supreme court of appeal for the empire, and to his person was attached the ancient sacrosanctity. Augustus showed the highest statesmanship in founding his power upon a metamorphosed tribunate rather than upon a metamorphosed dic tatorship, upon democratic rather than aristocratic traditions.
The name "tribune" was once again illuminated by a passing glory when assumed by Cola di Rienzi (q.v.). The move ment which he headed was in many respects extremely like the early movements of the plebeians against the patricians, and his scheme for uniting Italy in one free republic was strangely par allel with the greatest dream of the Gracchi.