Rudy Giuliani told the National Press Club that the door was still open for a Giuliani 2012 presidential campaign:

...Giuliani told the crowd, "I would have a hard time getting nominated," and said that he'd jump in only if the GOP field was looking "really desperate."
Asked why it would be so hard for him to become the nominee, Giuliani sketched a picture of a nominating process designed to keep Republicans like him — pro-choice, pro-gay rights (sort of) and (at one time) pro-gun control — from ever getting to the White House, despite the fact their views may be more in line with the general electorate than their more socially conservative opponents.

"I'm simply not that conservative on social issues," he said. "And I'm not willing to change just to become President."

Prepare for a shock: Rudy Giuliani just made sense. The Republican nomination process is skewed to keep Republicans hard-right. And if he invested his (still considerable) political capital into reforming that process, he'd be a hero. But he won't do that—it's easier to keep his brand alive by publicly flirting with the presidency and letting the desperate candidates play around in a funhouse version of America.