Tammany Hall
After the American Civil War the Democratic Party under Boss William Tweed's Tammany Hall gained a monopoly in both New York City Hall and the New York Legislature. Allegations of corruption rapidly grew as rumors spread that Boss Tweed and associates of Tammany Hall were laundering tax payers money in real estate and bribing New York State legislatures for favorable legislation. New York City workers under the Tammany Hall system were paid excessive rates on the burden of tax payers. By 1871, New York City residents and the press demanded that the corruption be investigated and cleaned up. On September 4, at Cooper Union, a large organization of reputed citizens was formed known as the "Committee of Seventy", that investigated the corruption of Boss Tweed's Tammany Hall Ring. Pierrepont was appointed to and actively served on the legislation commission of the "Committee of Seventy". The "Committee of Seventy" promised to thoroughly investigate Tammany Hall corruption and strongly encouraged honest voters to stop taking bribes from Tammany Hall at the polls during election. By the end of October 1871 the "Committee of Seventy" had successfully stopped funding Boss Tweed's Tammany Hall by court injunction effectively shutting down the corrupt institution. Tweed was arrested and thrown into jail.