Article I, section 5, of the United States Constitution empowers each house of Congress to judge the elections, returns, and qualifications of its members, along with the authority to discipline them for disorderly behavior. From 1793 to 1990, over 200 senators encountered challenges regarding their credentials, whether due to qualification issues, election irregularities, or disciplinary actions for offenses ranging from public corruption to providing aid to the Confederacy, as well as various acts that tarnished the Senates reputation. Researched and penned by the staff of the Congressional Research Service, this compelling chronicle unfolds each case in chronological order, revealing not only the political climate of the times but also the evolving understanding of what it truly means to serve as a United States Senator. - Summary by Joanne Turner.