Here is a new and interesting issue that has recently brought about many changes in the criminal defense world.
In a situation where a defendant is offered a deal by the prosecution (at one point earlier in their case) and for one reason or another, defendant's counsel misadvises him about his legal rights, defenses etc. regarding taking that deal, and then the defendant is convicted and sentenced there are some new cases that allow the conviction to be reduced or even overturned.
The two cases that are in play are Lafler v. Cooper and Missouri v. Frye. These cases raise issues about plea offers and ineffective assistance of counsel (IAC). In these cases, the defendants argue that they received deficient advice from their trial counsel.
In Lafler, the trial attorney incorrectly told the defendant that the prosecution could not establish an essential element of the prosecution's case (the intent to murder) merely because the defendant had shot the victim below the waist. The defendant relied upon that advice, and rejected the plea bargain offer.
The defendant was eventually convicted at trial, and sentenced to a much higher prison term than the plea bargain sentence.
In Frye, the defendant's attorney didn't even tell the defendant that there had been an early offer by the prosecution. The defendant eventually took a deal that was much worse than the previous offer.
The courts are now allowing convicted individuals some level of review (appeal/habeas corpus) where the facts support the proposition that a defendant was either misled, misadvised, or not informed of a plea bargain offer, and then is sentence or convicted to worse terms than the previous plea bargain offer.
These type of appellate reviews will apply to DUI (driving under the influence) cases, as well as an misdemeanor, or felony charges.