This article tries to demonstrate the anti-majority aspect of the Senate from a Mixed Government perspective and the separation of powers and its implications in forming Brazilian bicameralism. We will therefore show how Polybius’, through the Mixed Government, and Montesquieu s ideas, through the power separation theory, operated the division of classes and institutionalized political social separation. After that, based on articles of the authors of the Federalist Papers, we shall see how the checks and balances system has acted as a brake on the popular impetus. We will show how Senate is an important piece inside the system of brakes and counterweights intended to limit people s sovereignty. Finally, by analyzing the process to create bicameralism in Brazil, we will show how this system can maintain the privileges of a privileged economic class. Notwithstanding the argument that Senate is the house for representation of the Federate States, we will see that its main function has been that of conservatism and moderation.