Answer: Power to veto,
Number of judges and their tenure
Tenure of Chief executive
Explanation: In the Roman Government two (2) persons with the highest authority they are known as the Consuls with equal Veto powers while in the United States only one person has the highest authority known as the President with Veto powers.
The Roman Government have 8praetors(judges) who serve for just one year term while the United States have 9 supreme Court judges with a lifetime tenure.
The Roman Consuls are elected annually while the United States President is elected every four years.