[staunch]

> The Roman Republic was dead when Caesar won the civil war

The Republic had been in trouble for a long time. IMHO it officially died as soon as the First Triumvirate was created. Rome was in complete control of just three people for many years.

Pompey was the leading figure of the First Triumvirate, so arguably he deserves more blame than even Caesar for the downfall. The fact that more senators chose him over Caesar says very little about how truly republican any of them were by that point.

The war between Caesar's party and Pompey's party was really just a battle for who would be Dictator for life. Neither of them had any intention of handing real power back, because they could honestly tell themselves it was unlikely to fall into any better hands.

Had he won, Pompey would have continued to (through military threats) control the Senate the same way he had for many years prior to the civil war.