Denial is a natural first reaction when a man who fought crime is himself accused of crime. The Bush Administration's history of politically-motivated prosecutions, and especially of refusal to prosecute, make it entirely plausible that "they got Spitzer".
Spitzer says he did it. There's no indication that he didn't. It's best to skip the Seven Stages and go straight to Acceptance. (Although a short stop at Anger is appropriate: how could he be so stupid as to think he wouldn't get caught? Part of the answer is obvious: Alpha Males Think With The Wrong Head.)
Whether Spitzer resigns, or whether (like Scooter Libby and David Vitter, he waits until there's an actual jury verdict against him) is up to him and the voters of New York State.
But one thing is for sure: Spitzer isn't going to get our troops home from Iraq, or our jobs back from China, or our nation's honor back from a White House that loves torture.
Although, for the moment, he has taken the Hypocrisy Prize from the GOP.
Don't grieve; they'll have it back soon.