Salva sis demidiva

Scripsisti:
I think it's possible - POSSIBLE - Pompey and Caesar might have held a joint consulship, pushed through some reforms for their respective armies, and retired in glory to be Princeps Senatus, whatever - or Caesar would have gone off happily to conquer Parthia UNDER the control of a Senate he could work with.

Possible, yes, even after things had begun. Crassus had to be avenged. But would it have been Caesar rather than Pompeius who would conduct the campaign against Parthia? Pompeius would have been the better choice, and the more likely I think. And would that not have caused political tension, no matter which was allowed to remain in Rome to consolidate his position?