The Oxford History Of The Classical World

The next princeps, Gaius, came naked to empire, so that, as Dio (59. 3) observed, 'he had to be voted in a single day all the prerogatives which Augustus over so long a span of time
had been voted gradually and piecemeal, some of which indeed Tiberius had declined to accept at all'; such too was the position of Claudius, Nero, and the four Emperors of 68/9.
Hence later writers, puzzled by the absence of such an enabling grant for Tiberius, may have been left floundering or guessing, ascribing delay to a supposed concern about
disaffection in the Rhine and Danube legions or wariness about what Germanicus might do-although such threats, had they been real, should have called for speed rather than
indecision. Apart from that, the 'accession debate' (Tacitus, Annals 1. 11-13) was badly mismanaged, with Tiberius clumsily or deviously rehearsing or inviting other options (when
in practice all that was needed was an expression of his readiness to take over the role of Augustus), and in the end not so much saying 'yes' as ceasing to say 'no'.