I think the Rubicon was more this election. Caesar was in a position where, if he didn't bring his army to Rome, his political enemies were going to destroy him. Trump was in a position where, if he didn't win the election, his political enemies (and the legal cases arising from his various unusual activities) were going to destroy him.
But I wonder if that's really where we are. I wonder if we're not more at the time of Marius and Sulla, and the real Caesar is still 40 years away.