Rudolph William Louis "Rudy" Giuliani is an American lawyer, businessperson, 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 as the previously "Teflon Don" to prison for life via testimony brokered in a deal with Sammy the Bull—a renown that launched Giuliani, viewed as tough on crime, into politics.
Mayor of New York City for two terms starting in 1994, Giuliani hired a new police commissioner, William Bratton, who applied the broken windows theory of urban decay, whereby disorder and violations lead to fear and felonies ruining cities. Within several years, Giuliani was widely credited for major improvements in the city's quality of life and rates of violent crimes, although later researches have found the timing largely coincidental.