Go read the Washington Monthly forthcoming cover story by Rachel Morris on Rudy Giuliani and executive power:
... Giuliani also unashamedly flouted the First Amendment to crush dissent both inside and outside his government. He lost thirty-five First Amendment cases in court. His administration was found to have shut down or delayed legal protests, illegally prevented its own employees from making protected public statements, and illegally prevented New Yorkers from gathering on the steps of City Hall. The Second Circuit Court of Appeals took the unusual step of reprimanding the administration, noting, "[W]e would be ostriches if we failed to take judicial notice of the heavy stream of First Amendment litigation generated by New York City in recent years."
In all of these cases, Giuliani was ultimately checked by the courts, even if his strategy had gained him valuable time. Sometimes, though, he got away with skirting the law because no one was able or inclined to restrain him. ...
As his term progressed, Giuliani became increasingly unscrupulous in his manipulations of the bureaucracy to avoid oversight and transparency. He was especially sensitive about any agency charged with scrutinizing the NYPD. ...
Giuliani understood that the currency of oversight is information, and he exercised more control over information than any mayor in recent memory. His administration denied information to the public, borough presidents, the city council, and the public advocate. ...
By Giuliani's own admission, he would, as president, perpetuate many of Bush's boldest assertions of presidential authority. In 2006, Giuliani told the Wall Street Journal that he would probably keep the detention center at Guantanamo Bay open ... Giuliani has also indicated that presidents have the power to indefinitely detain American citizens without trial. At a debate, he declared himself opposed to torture but refused to say whether he would outlaw waterboarding, instead offering that interrogators should perform "any method they can think of."
What is most disturbing is the likelihood that a Giuliani administration would venture beyond the expansive claims of executive authority staked out by the Bush White House. ...