Was the assasination of Caesar justified?

[Nathan Ross]

Is conspiratorial vigilantism ever justified by anyone except the conspirators?

As others have mentioned above, Tyrannicide (which is pretty much what you describe!) was seen as a laudable and virtuous act by the Republic. This was the defence of the conspirators - they merely had to wave their bloody knives, shout that they had slain a tyrant, and everyone would applaud them as heroes. Unfortunately, the assembled senators were horrorstruck by the spectacle and ran for their lives... as did the conspirators... Not a good day for pristine republican virtue!

By that logic, Augustus could never have existed, nor any of his successors - yet the ages changed and the principate was born. How was this seen and judged at the time, which was still a 180-degree swing from the murder of Caesar?

Perhaps the greatest error of Brutus, Cassius and co was in believing the rhetoric of liberty they had been fed from birth? Excepting ambitious political players like Cicero, or inflexible idealists like the younger Cato, the majority of Rome's political class probably had the maturity and pragmatism to recognise that a monopoly of power had become the inevitable outcome of a murderously competitive oligarchy and a generation of civil war. They may have regarded Caesar as a tyrant, but at least he wasn't threatening them with imminent death - his successor, on the other hand, might...

By the birth of the principiate, there was a new generation in power - the old political class (all those great families soiled by association with Sulla or Marius) had died off or retired from public affairs; the new men in the senate had grown up with the idea of single rulership, either as a threat or an ideal, and found it far easier to accommodate themselves to the system.