Final answer:
The detail of Julius Caesar leading his army to attack Rome, crossing the Rubicon, and eventually declaring himself dictator reflects the passage's central idea about his rise to power and the shift from republic to empire.
Step-by-step explanation:
The detail in the text that best reflects the central idea of the passage from Dictatorships by Hal Marcovitz is the moment when Caesar refused the Senate's order to disband his army and instead led a direct assault on Rome by crossing the Rubicon River.
This action marked the transition from a republic to a dictatorship and underscored Julius Caesar's consolidation of power, ultimately leading to his declaration as dictator for life. It shows Caesar's resolve to assert his authority over Rome and his defiance of the existing political structure. His rise to power was characterized by strategic alliances, military conquests, and political maneuvers that exploited the Senate's weakness.
Critical to understanding Caesar's grip on power is how he leveraged his military leadership and popular support to challenge the established order. Despite the Senate's resistance, Caesar's successful campaigns and reforms cemented his status, leading to significant changes in the Roman government structure. His actions followed, and some would argue escalated, a pattern initiated by figures like Marius and Sulla, who had previously used their armies to exert influence over Roman politics.