The Gracchi Land Reforms
As Rome's conquests enriched a tiny elite and flooded the land with slaves, the small citizen-farmers who were the backbone of its army were pushed off their fields. Two aristocratic brothers, Tiberius and Gaius Gracchus, tried to redistribute public land to them — and both were murdered by rival senators for it, shattering the unwritten rules of Roman politics. Their deaths opened a century of factional bloodletting: too many ambitious elites competing for too few honors, the slow engine that would grind the Republic to dust.
More aspirants to elite positions are produced than there are seats; surplus elites turn to factional conflict.