The study of ancient Roman government reveals a civilization that cycled through almost every form of government from oligarchy to tyrant and emperor. It's not until the period leading up to the 1st century B.C. that the influence of Rome on modern government is clearly visible in history through when the nation was a republic and control belonged to the Senate. Roman government was made up of an executive, legislative and judicial branch with varying responsibilities.
In times of peace, the executive branch of ancient Rome comprised two consuls, elected by Roman landowners for two-year terms only. During times of crises caused by war, a single dictator was elected for six months to oversea the protection and expansion of Roman interests. At all times, the executive branch also contained various bureaucrats who were in charge of arranging festivals and conducting censuses. By contrast, the United States is a democracy with only one leader in the executive branch, the President.
The most influential members of the legislature in Rome were those in the Senate. This large body of elected land owners decided how state money was spent and what projects were viable for state funding. The Senate also took control of foreign policy -- in particular, the many wars Rome was engaged in as it expanded its territory throughout the 1st century B.C. The roles assigned to individual senators were allocated by the two consuls of the executive branch.
The judicial branch of ancient Roman government was very similar to the courts, particularly the Supreme Court, of modern-day America. Six judges were elected on a biannual basis to administer the law of the land to those who broke it. Unlike the judges in the modern U.S., the Roman judiciary could actively create sentences and punishments, instead of merely following past precedent or the sentencing law handed down from the legislative and executive branches.
The great buildings that house various branches of the American government are inspired by Roman architecture. Perhaps the most obvious example of this is seen in the Supreme Court. Cas Gilbert's design draws its inspiration from Roman temple buildings. The staircase, raised podium and the columns would not be out of place in the Roman Republic. Similarly, the white marble on the Supreme Court and throughout Washington, D.C., was consciously selected to mimic the architectural splendour of ancient Rome. Fluted Doric columns reflecting Roman architecture without any decorations at the top or base are present in many American buildings including The Federal Hall in New York City.