Rudolph ("Rudy") Guiliani (born 1944) is the former two-term Republican mayor of New York City. He presided over the city when the 9/11 terrorist attack occurred. He is running for the Republican nomination for president of the United States in 2008.
Guiliani is liberal on social issues such as abortion, gay rights and guns. In 1994 Guiliani made a highly public endorsement of Democrat Mario Cuomo in his reelection race for governor of New York against Republican George Pataki, who won anyway.
Guiliani did attract some support by conservatives by emphasizing law-and-order as mayor, which included reducing crime in New York City. When U.S. Senator Daniel Patrick Moynihan announced that he would retire in 2000, Guiliani raised millions of dollars from conservatives in an apparent attempt to defeat Hillary Clinton for that seat. But after Guiliani raised all that money, he declined to run and many have no idea what happened to their donations.
The National Catholic Register is advising Catholics not to vote for Rudy in 2008 because he is pro-choice. 
Prior to becoming mayor of New York City, Guiliani served as a prosecutor for the Department of Justice in the 1980s. As U.S. Attorney, Guiliani presided over many high-profile arrests and prosecutions, many of them apparently publicity stunts. Acquittals in the Southern District of New York are very rare, but juries acquitted former Miss America Bess Myerson and former Philippines First Lady Imelda Marcos of charges brought by Guiliani.
In another display of publicity, Guiliani began prosecuting insider trading after an investigation by the Securities and Exchange Commission uncovered some illegality. Guiliani then arranged for two Wall Street brokers to be handcuffed, put up against the wall, and arrested at their offices. They were subjected to humiliating publicity, but were apparently innocent: no charges could even be brought against them.
Guiliani helped arrange for the Republican National Convention to be in New York in 2004, where he often promoted himself before delegates at special events. But Guiliani's only contribution to the Bush Administration has been to persuade Bush to nominate Guiliani's friend Bernard Kerik as the head of Homeland Security after the 2004 election. Numerous scandals then surfaced about Kerik and he withdrew.
Guiliani's personal background is unlike most presidents. He avoided the Vietnam draft first by obtaining a deferment by attending law school, and then by obtaining a dubious "civilian occupation deferment" to serve as an allegedly essential employee -- which was merely as a law clerk for a judge. Guiliani has been married three times. His first marriage was to his second cousin, Regina Peruggi. They were married for 14 years, before Giuliani had their marriage annulled by the Catholic church. His divorce from his second wife to make it possible to marry another woman consumed enormous time and media attention from 2000 to 2002.
Giuliani is leading in most polling for the 2008 Republican nomination.