That is a Makhloket between the Ibn Ezra, and the Abarbanel on side, who hold that a weak Sanhedrin that appoints dictators as needed, like in the time of the Shoftim.
The Rambam and Sefer HaChinuch hold that a Malkhut(Kingship) that rules with the Sanhedrin with specific powers given to each is the correct system.
Mind you this is on the national level local government is Democratic