This article examines references to the Senate of the Roman Republic in several of the early writings of Henry Adams. It looks particularly at his journalism and reform writings of the 1860s and 70s, and culminates in an analysis of his novel Democracy from 1880. Adams’ great-grandfather John was a leading proponent of a senate in the deliberations over the US Constitution. For Henry, the intellectual and political legacy represented by the Senate crystallized political problems, including the appropriate balance of power, the nature of representation, the threat of tyranny, and the dangers of party and personal corruption. Adams was closely engaged with historiographical debates in the UK and Germany over ancient republics and the lessons they held for modern ones such as USA. His portrait of the corrupt senator Silas Ratcliffe in Democracy resonates in particular with Theodore Mommsen’s treatment of Cicero. In The History of Rome, Mommsen rejected the heroic image of Cicero as the father of his country and presented instead a portrait in which the Roman senator’s self-interest predominated. At the same time, he burnished Caesar’s image as a dictator who loved the people. Mommsen’s critique of Cicero echoes through Democracy, which concludes in some despair over the prospects of the American democratic system while offering no compensatory, heroic Caesar figure.