Most would agree that Spartacus' rebellion was ultimately doomed to failure, given that Rome had vast reserves of manpower to throw against them, and had much to lose if they didn't do anything about him quickly enough. I was wondering how quickly the Roman Republic could decline if Sparatcus was able to come to an agreement with the Cilicians if they were to agree to capture and divide certain regions on the island of Sicily. As a prized province and source of food, this is something the Romans won't ignore for ever, and would bring their forces to bear on the takeover as soon as they could spare the troops.
But maybe the POD that would allow for this to come to pass may not be within the slave rebellion itself, but lie elsewhere with the two concurrent conflicts of the 70's BCE: The Third Mithridatic War in the eastern Mediterranean, and the Sertorian War in Hispania.
During a certain battle of Sucro in 76 BCE, Gnaeus Pompey apparent came close to being captured by the forces of the Proconsul Quintus Sertorius after refusing to wait for reinforcements by the general Quintus Caecilius Metellus Pius. If perhaps Pompey was killed in the attempt to by the enemy to take him alive, and the three legions who he had inherited from his father and served as his own private army perhaps switches sides with the Sertorian cause, giving the Ibero-Romans an upper hand in the conflict.
Reinforcements to the campaign in Asia led by Lucius Licinius Lucullus and Marcus Aurelius Cotta would be delayed further, as they combat the armies of King Mithridates VI of Pontus. Mithridates, who was in league with the Cilicians pirates, helps wear down the legions campaigning in Asia Minor.
This leaves Marcus Licinius Crassus, as one of the richest if not the richest man in Rome, who had enjoyed much success against the slave army. However, with the situation worsening abroad, I wonder if Crassus might take the opportunity to press whatever advantages he had over his peers in the Senate, in a situation where a major rival like Pompey being dead for nearly four years. If this causes a serious schism within the Republic on Italian soil, then maybe Spartacus, in that situation, might take the chance to persuade the Cilicians to work with him in capturing key cities in Sicily.
The arrangement being that the Pirates get to keep cities like Syracuse, Akragas, and Messina as bases from which to operate, while Spartacus' army would migrate into the Sicilian country, and capture a number of inland towns and villas, recruit thousands of slaves working there, and carve out some territory in which to entrench themselves and put down roots.
Thoughts?