Giuliani scares me.
I am worried about the intersection of two aspects of a possible Giuliani presidency. The first is his apparent belief that a Democratic political victory will lead to dead Americans. The second is his natural predilection towards authoritarianism.
I can think of two instances in which two similar factors combined with bad results. The first was in WW2, when FDR and the governors of Western states believed that Japanese Americans were a threat to the United States. That belief, combined with the domestic power of the military (led by some racist generals), led to American concentration camps for 110,000 Japanese Americans. Fred Korematsu challenged the power of the government to implement concentration camps, and the Supreme Court sided with the government. Not a proud moment in American history.
The second instance is Richard Nixon and Watergate. Nixon believed that journalists, protesters, and people inside his administration were deliberately undermining him , the United States, and its efforts in the Vietnam War. Combined with Nixon's fetish for secrecy, covert actions and executive power, this almost led to the implementation of domestic detention camps for anti-war protesters under the Huston Plan. The only reason it wasn't implemented, it seems, was J. Edgar Hoover's personal dislike for Tom Huston combined with a fear for his legacy, as he was getting old. (1)
In both of these cases there were two variables. The first was the identification of a domestic threat. The second was the failure of oversight and of leadership, from FDR and the Supreme Court in the first instance, and from the White House and F.B.I. knowingly and willingly breaking the law combined with the total lack in institutionalized legislative and judicial oversight in the second instance.
A Giuliani presidency would have both variables. He has identified a domestic threat, arguing that Democratic victories will lead to dead Americans. In terms of oversight, Giuliani will be as bad as Bush in terms of secrecy and "Executive Privilege," and some say he'd be worse(2). He's already admitted that, as President, he would want the authority to arrest American citizens with no review (although he'd use the power "infrequently").
Giuliani is not a person I can trust with Presidential power.
(1) Christopher Andrews, For the President's Eyes Only, pages 366-369.
(2) "The first serious problem is structural and political: A man who fought the inherent limits of his mayoral office as fanatically as Giuliani would construe presidential prerogatives so broadly he’d make George Bush’s notions of “unitary” executive power seem soft." Jim Sleeper. Why Rudy Giuliani Really Shouldn't Be President.