“The difference between the republic and empire is one of aristocracy (Senate) vs. monarchy, so the parallel is not exact.”
Given that consuls in the Roman Republic were elected for one-year terms and could not be immediately reelected (except during the decline of the Republic), Hoppe’s argument ought to apply to them, i.e., one might expect them to have had an incentive to act with high time-preference rates. Which incentives (besides the ideology of pietas) did the Romans use to make their consuls more farsighted?
“Are you trying to compare the Roman government to some other State?”
This would also be interesting (e.g., a comparison between Rome and other ancient civilizations such as Egypt or Greece), but I was mainly trying to compare various periods within Roman history. Can you recommend an essay or book on the history of Roman governance and law and the effects of institutional changes on policy?