Complex sentence: It was seen by some as a violation of the right to a trial and led to charge of repressive governance, and gave the populares ammunition with which to challenge the notion of aristocratic dominance in politics and the prestige of the senate.
Split into simpler sentences: It was seen by some as a violation of the right to a trial and led to charge of repressive governance. It gave the populares an issue to challenge the notion of aristocratic dominance in politics and the prestige of the senate.