No, you don't get a do-over in the legal system:
Larry Craig Denied Withdrawal By Stern, Unforgiving Judge
Washington, Oct. 4
Turning a deaf ear to Craig’s pleas, the judge informed him that his initial plea to submit himself to the judge’s discretion was given “unambiguously and without coercion”. In light of this fact, the judge would not permit any withdrawal, and swore to see to it that Craig took the full punishment coming to him.
Craig was visibly shaken by the intensity of the judge’s position. “I’ve never been in this situation before in my life,” Senator Craig announced between what sounded like gasps of disbelief. “I cannot recall ever having been this far on the bottom before, and I don’t quite know what to do next”.
Questioned later outside the courtroom, Craig was still struggling to come to terms with this latest development:
"It's outrageous. The judge seemed to think that, just because I pleaded guilty that I meant it or something. And then he went on about this stuff called 'accountability' and 'personal responsibility'. What the fuck was that all about?"
As Craig was led away by his lawyer, he was heard to exclaim, "Sentencing? Sentencing? What the hell!? How can I be guilty? I'm a Republican, for God's sake!!"