Sulla

Hi there, I was wondering why the Sulla constitutional reforms proved to be a short-lived one? Why did they not last after his retirement?

I haven’t thought about this aspect of Roman history in years, so I’m probably the last person to knowledgeably comment on Sulla’s reforms.

It seems to me, however, that Sulla’s numerous extraconstitutional activities (including his ruthless proscriptions) undermined any hope of legitimacy and broad acceptance of his reforms. His actions, if anything, helped to undermine and eventually end the Republic.

Future military strongmen (such as Pompey and Julius Caesar) would soon challenge these reforms after his death.

One problem with the reforms was Sulla’s destroying the Republic’s long-held balance of power between the Senate and the non-senatorial ranks of the tribune of the plebs. By increasing the number and power of the Senate, as well as giving the Senate control of juries, he insured discontentment of the tribunes and the masses. The reforms also greatly diminished the power of the tribunes, which left the plebs with no opportunity to legally act on their dissatisfaction. 
 

It wouldn’t take long for a populist like Caesar to later topple the whole Republican edifice.

https://www.worldhistory.org/article/1481/sullas-reforms-as-dictator/

Caesar didn't topple the republican edifice, he simply took control of it by emulating then exceeding Sulla's methods. The Imperial period was not a separate regime either, just good old SPQR but now with single person domination in diluted form (though it got a lot less conformal from Caligula onward).

What Caesar did was treat the Senate with respect, at least outwardly, which is significant given how contentious he was earlier in his career. Of course, this behaviour was just realpolitik - we are talking about a character who along with Crassus plotted a mass slaughter of senators to grab power. However, Caesar did allow (or encourage) the Senate to swell to ovr a thousand members with enough dodgy characters to make senatorial debate even less decisive that it already was in the period of lapsed Princeps Senatus leadership.

Proscriptions were not quite an obstacle. The Seconds Triumvirate were especially keen on them and Octavian, though initially reluctant, the most ruthless of all. Yet all that seems to have been set aside once Octavian decided to continue after Antony's death and became Princeps Senatus. After all, those that survived had less to worry about.

As for Sulla's legal machinations, we are dealing with a period where politics was wavering ever more precariously between radical and traditional politics, so once Sulla was out of the way not really suprising that some laws were repealed or changed.

Homework ?

In general the Senate, even reinforced by the new members co-opted by Sulla did not vigorously defend the Sullan system against the many discontented elements that opposed it (Italians, exiles, those who's property had been confiscated, equites and businessmen, the plebs).

The thrust of Sulla's reforms was to hamstring the tribunate and to control the military commanders.  Agitation to emancipate the tribunate was almost immediate.   The tribunate was of great value to any aspirant for a political career as it provided a stage as champion of the people and an opportunity to propose laws to benefit powerful patrons; and the plebians looked to the tribunes for land allotments and cheap grain.  As soon as 75 BC the consular lex Aurelia ended the prohibition on tribunes holding higher office (and opened the juries to equites, apparently without serious opposition) and Pompey and Crassus removed the other restrictions in 70.

Catullus and Senate managed to crush the revolt of Aemilius Lepidus in 77, but agreed to send Pompieus and his army to Spain to deal with Sertorius though he was still an eques, and sent Antonius Creticus against the pirates with imperium infinitum. Then came the Slave war.  The failure of the consuls to deal effectively with it, and the absence of the Luculli in the East left command in Italy to Crassus who succeeded in defeating Spartacus.  Pompeius returned from Spain in time for the consular elections for 70, the two were duly elected and dismantled much of what remained of Sulla's settlement.

The Sullan senate was simply not monolithic in its support of the strictures of the Sullan system.  Most were not adverse to a gradual loosening of oligarchic control when circumstances required it.