Rudolph William Louis "Rudy" Giuliani is an American lawyer, businessman, former politician, and public speaker from New York. Politically a Democrat and then an Independent in the 1970s, but a Republican since the 1980s, Giuliani was the federal attorney for New York state's southern region in the 1980s who prosecuted pivotal cases against the Italian Mafia and against corrupt corporate financiers. Giuliani reputedly tamed organized crime—most famously leading the case that sent boss John Gotti, the "Teflon Don," to prison for life based on testimony brokered in a deal with Sammy the Bull. That accomplishment, which won Giuliani a reputation for being tough on crime, helped to launch him into politics.