Like Oliver Cromwell, Barack Obama is more conservative than his core supporters. (Cromwell was originally against executing, or even deposing, Charles I.) An electoral sweep, backed with a movement that can still be mobilised against a recalcitrant Congress, would give President Obama an authority greater than any of his predecessors since FDR. In this scenario a more vindictive politician could get away with putting Bush and Cheney on trial for treason: fortunately for the republic as well as White House malefactors, this won't happen. Obama clearly has the moderate temperament of Augustus or William the Silent rather than the hubris of Julius Caesar or Napoleon III.
They do know that Augustus got to rule as a peaceful old uncle by dint of having had (as Octavian) everybody who could possibly look crossways at him executed on day one? Think Cicero.
That was what pissed me off about Gladiator. Roman generals didn't get thrown into paroxysms of revenge when people massacred their families; happened all the time, something you could have a good laugh at over a cleansing ale next time you met over the negotiating table, something you'd done yourself to the families of your conquests after you'd had them march behind your chariot in chains at your triumph. No biggie.
Listen to Octavian and Anthony in Anthony and Cleopatra haggling over the proscriptions - ok, you can kill my uncle, but only if I get to kill your brother - Shakespare didn't make that mistake.