[quote Witchend]@DGRossetti
Didn't Caligula make his horse his heir or something like that?[/quote]
en.wikipedia.org/wiki/Incitatus
Historical opinion tends to swing between myth and fact.
However, what isn't disputed is that old "little boots" came to a very messy end at the hands of the Praetorian guard. Thus setting them up for centuries of emperor-making, until they got on the losing side with Maxentius and Constantine disbanded them.
The point is while Caligula was in full loon mode, nobody dared say no. And that's probably part of what is holding saner Republicans back. Also, unless and until they perceive a threat to themselves, they have no motive to intercede. After all it's been clear for decades that no one actually gives a shit about the people. If they're suffering and you aren't, why would you ever do anything to change that ?