In his statement, Eliot Spitzer notably didn't announce his resignation.  Rather, he said the following:

"I do not believe that politics, in the long run, is about individuals. It is about ideas, the public good and doing what is best for the state of New York."

Spitzer may simply be waiting to resign, as doing so could be one of the conditions of a plea agreement.  As a former Attorney General of New York, he presumably is well positioned to understand criminal law and the most advantageous way to handle this problem.

But his wording above is raising speculation that he may not plan to resign.  If that's true, it's part of a new and troubling pattern in American political life.  It's not a partisan thing; Larry Craig's refusal to resign was another manifestation of it. 

The whole idea, pioneered by you-know-who and enabled by you-know-who-else, is that illicit sexual behavior and the scandals resulting therefrom can be brazened out by the insistence that they are irrelevant to the discharge of public duties.  As I argue in my book, it's all part of a new ethical calculus concluding that -- uniquely in the constellation of virtues -- sexual morality is a subjective and purely personal matter that's of relevance only to "religious" people (or else prurient and "judgmental" ones), even when it impacts the public.   

All of us are human, all of us are sinners, no one is perfect.  Certainly, there but for the grace of God go any of us.  But that doesn't mean that there should be no standards.  In particular, it's unfortunate if and when public officials conclude that sexual behavior that's  deeply disgraceful (not to mention illegal) doesn't merit resignation.  It degrades our culture, makes others complicit in condoning conduct that shouldn't be condoned, and normalizes behavior that's wrong.  

No doubt it's a sad day for Governor Spitzer -- long a Democrat shining light -- and his family.  They merit our compassion on a personal level.  But it's appropriate and right that the Governor resign.