Giuliani doesn't want to be Senator, IMHO. His utility is limited to knocking off some other liberal statist like Hillary, Schumer or Spitzer, the NY Attorney General, who wants to be go for a statewide office. If Giuliani returns to elective office, he'll disappoint both conservatives and small 'l' libertarians. He would be worse than Arlen Specter. At least Arlen gets an A from the NRA.
"who wants to be go for" = "who wants to go for"