Would there have been a non-ASBish way of bringing about a "constitution" or political settlement in ancient Rome that engendered greater stability, without the ruinous civil wars, coups, assassinations etc? I was considering two cases (these are just a few random ideas):
a) A stabler late republic, avoiding Marius, Sulla etc (or being taught a lesson the first time). Perhaps this could have been achieved by introducing a strong barrier between the political and military spheres. Military officers would have received a professional education and would not have been allowed to hold political office. They would still have to rotate senior officers regularly to stop them building too much personal loyalty - a cohort, or a unit the size of a modern batallion, would be the largest unit with a permanent commander, and people would not be allowed to raise legions on their own initiative. The magistracy would need to be far less politicised and restricted to those with extensive backgrounds in the field of law, and the concept of imperium would need to be strongly revised, especially with respect to provincial governors and generals. A fully-fledged, apolitical civil service would also have helped. I'm not sure if any of that would be enough, but overall, I think greater professionalisation in most fields is key. But what would have been needed to trigger such reforms, and is it remotely realistic?
b) A stabler empire. Most of the above would still apply - perhaps at the start of Augustus' reign, the senate would have been accepting of that sort of thing if they could be convinced that there would be fewer civil wars, and provided there would also be enough checks and balances on the power of the Princeps - but the emperors also need to address the problem of succession. I think the easiest way to achieve this would have been if the Julio-Claudian dynasty had actually been a proper father-to-son dynasty , and over time, the principle of hereditary succession would have entrenched itself as the Principate became more monarchic. The Princeps, and "princes of the blood" (under a very clear order of succesion, with one being designated as the heir, and the others as possible cadets) would be the only ones to bridge the political and military spheres, because the Princeps would have to be capable of running the executive branch of the government and of being the commander-in-chief. I don't think this would have provoked any negative associations with the Kings of Rome, because the Kingship was never properly dynastic either, but again, is all this ASB?