How did the dealths of the Gracchus brothers change roman politics?

The killing of Tiberius Gracchus in an attack on him and his supporters and the suicide of his brother Gaius following an attack on his supporters marked the beginning of violence becoming a major factor in Roman politics. Both brothers, at different times, entered in conflict with the senate to press for an agrarian reform to redistribute land to the poor. Both times the senators attacked their opponents. The first time they hired thugs and 300 people were clubbed to death. The second time mercenary archers from Crete were hired and a mob was mobilised against the opponents. After the clash, 3,000 people were killed without trial.

This was the beginning of the conflict between populares and optimates. The former was a political faction which championed the cause of the poor and wanted reforms to help them. The latter was a conservative political faction which stood for the interests of the aristocracy and opposed the reforms. Its power base was the senate. Violence often broke out between these two factions, which also fought civil wars against each other.