The ever-insightful John Judis has a lengthly, fascinating article up on the New Republic site evaluating Rudy Giuliani’s political and governing philosphy based on his upbringing, education, and experience as mayor of New York.
In terms of Giuliani’s early background, Judis basically concludes that while Rudy is a pretty crummy Catholic when it comes to personal conduct, he drank deeply from a Catholic Aristotelian tradition of political philosphy that has been known on occasion to lead from a mild communitarianism to a dangerous authoritarianism (viz, the sad history of European Catholic political thinking in the first half of the twentieth century).
Of more immediate interest is Judis’ fine analysis of the false and frightening analogy that Giuliani often draws between his anti-crime campaign in New York and how he would “police” the world as president:

In a recent essay for Foreign Affairs, [Giuliani] wrote: “I know from personal experience that when security is reliably established in a troubled part of a city, normal life rapidly reestablishes itself: shops open, people move back in, children start playing ball on the sidewalks again, and soon a decent and law-abiding
community returns to life. The same is true in world affairs. Disorder in the world’s bad neighborhoods tends to spread. Tolerating bad behavior breeds more bad behavior.”
This is a foolish analogy. In policing the world, the United States cannot claim to be enforcing its own laws; we lack legitimacy to do so, as we found after invading Iraq. When the NYPD went into poor neighborhoods, it was not an occupying force; when the U.S. military took over Baghdad, it was, and it suffered the consequences. Some of the “neighborhoods” Giuliani wants to clean up, such as Iran, possess their own armies and can call on other “neighborhoods,” such as Russia and China, to deter an attempt to punish them for bad behavior. In short, the world is not New York writ large, and the trade-offs between authority and liberty look very different from the White House than from Gracie Mansion. But these distinctions seem lost on the man who aspires to be the next mayor of the United States.

Judis doesn’t mention the grand irony of the front-running Republican candidate using a law enforcement paradigm for anti-terrorism policy, particularly given Giuliani’s large platoon of neocon advisors. (It’s supposed to be Democrats who don’t understand this is World War III, not gang-busting). But to the extent that Rudy seems to have convinced a lot of voters that his record in reducing violence in New York is the best reason to believe he can reduce violence around the world, Judis has performed an invaluable service in showing how ridiculous a credential that really is, and the danger to both national security and civil liberties that a Giuliani presidency would pose.