Final answer:
The key difference is that Roman consuls only served for a year, while the highest official in Venice served for life. Roman consuls had significant power including military authority, with checks and balances like term limits and dual consulship.
Step-by-step explanation:
The key difference between the constitutions of the Roman Republic and the Venetian Republic is that the highest officers in the Roman Republic, known as consuls, only served for one year. In contrast, the Doge of Venice, which was the highest official, served for life. During their one-year term, Roman consuls held significant power, including imperium, and were in charge of the administration and the military, making them pivotal figures in Roman governance. Importantly, the constitution of the Roman Republic provided checks and balances through term limits and the requirement that each year, two consuls were elected to keep each other's power in check. Also, unlike the Doge of Venice, Roman consuls possessed military authority. Over time, both plebeians and patricians were able to hold the position of consul, reflecting the complex and evolving nature of the Roman Republic's political system.