Rudolph William Louis "Rudy" Giuliani (/ˈruːdi ˌdʒuːliˈɑːni/; born May 28, 1944) 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.During his second term as Mayor of New York City, Giuliani hired a new police commissioner, William Bratton, who applied the broken windows theory of urban decay, which holds that 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 researchers have found the timing largely coincidental. While still mayor, he ran for US Senate in 2000, but withdrew upon diagnosis of prostate cancer. Still, he gained international fame as New York City's leader in the immediate aftermath of the 9/11 attacks in 2001. Giuliani was named Time magazine's Person of the Year for 2001, and was honorarily knighted in 2002 by the United Kingdom's Queen Elizabeth II.In 2002, Giuliani founded Giuliani Partners (security consulting), acquired and later sold Giuliani Capital Advisors (investment banking) and joined a Texas firm while opening a New York office for the firm renamed Bracewell & Giuliani (legal services). Giuliani sought the Republican Party's 2008 presidential nomination, and was considered the early front runner in the race, before withdrawing from the race to endorse the eventual nominee John McCain. Giuliani was considered a potential candidate for New York governor in 2010 and for the Republican presidential nomination in 2012. However, Giuliani declined all races and instead remained in the business sector.