The Roman Republic had several influences on the framing of the U.S. Constitution, with one of the most significant being the concept of a mixed government and the separation of powers.
In the Roman Republic, power was divided among different branches: the consuls (executive), the Senate (advisory body), and the popular assemblies (representative body). This structure inspired the framers of the U.S. Constitution to create a system that included an executive branch (the Presidency), a bicameral legislature (Congress, consisting of the House of Representatives and the Senate), and an independent judiciary (the courts). This separation of powers aimed to prevent any one branch from gaining too much power, promoting a system of checks and balances.
Therefore, the influence of the Roman Republic can be seen primarily in the adoption of these principles of separation of powers and the establishment of a mixed government structure in the U.S. Constitution.