Why did Augustus stop serving as consul every year after 23 BCE?

Augustus stopped serving as consul every year after 23 BCE primarily because his monopolization of the office had begun to offend the Senate, making a new arrangement necessary to maintain the cooperation of the senatorial class, which was essential for civilian government.1

Additionally, Augustus had been facing health issues and political conspiracies, leading him to seek a constitutional structure that provided him with supreme authority while avoiding the practical inconveniences and potential resentment associated with holding the consulship. In 23 BCE, he vacated the consulship and instead acquired the tribunician power (tribunicia potestas) for life. This power offered several strategic advantages:21

• Democratic Aura: It was traditionally associated with the protection of the plebs, which helped Augustus project a more "democratic" image and avoid the appearance of being a military despot.12
• Legislative Authority: It granted him the right to convene the Senate and enjoy priority in bringing business before it.12
• Administrative Flexibility: He was also invested with imperium proconsulare majus, a high command that was superior to that of any other proconsul, allowing him to intervene legally in any province.12

By shifting to these powers, Augustus successfully maintained his supreme position in the state while ostensibly respecting republican traditions.12