Three similarities between the Roman Republic government and the United States government are that both have a system of checks and balances, meaning that no one part of the government can become too powerful. They both also use elected representatives, where citizens vote for people to make decisions for them. Lastly, both governments value the idea of a rule of law, where laws apply to everyone equally.
Three differences between the Roman Republic and the United States government are that the Roman Republic had a Senate made up of wealthy patricians, while the U.S. Senate includes representatives from all walks of life. The Roman Republic allowed for a dictator to take control in emergencies, but the U.S. government does not have a position like that. Also, citizenship in Rome was limited to certain people, while in the U.S., citizenship can include anyone born here or who goes through the naturalization process.