If the defendant makes the showing:
Where a defendant shows ineffective assistance has caused the rejection of a plea leading to a more severe sentence at trial, the remedy must “neutralize the taint” of a constitutional violation but must not grant a windfall to the defendant or needlessly squander the resources the Stateproperly invested in the criminal prosecution...
If the sole advantage is that the defendant would have received a lesser sentence under the plea, the court should have an evidentiary hearing to determine whether the defendant would have accepted the plea. If so, the court may exercise discretion in determining whether the defendant should receive the term offered in the plea, the sentence received at trial, or somethingin between.
However, resentencing based on the conviction at trialmay not suffice, e.g., where the offered guilty plea was for less serious counts than the ones for which a defendant was convicted after trial, or where a mandatory sentence confines a judge’s sentencing discretion. In these circumstances, the proper remedy may be to require the prosecution to reoffer the plea. The judge can then exercise discretion in deciding whether to vacate the conviction from trial andaccept the plea, or leave the conviction undisturbed.
In Frye:
The Sixth Amendment right to effective assistance of counsel extends to the consideration of plea offers that lapse or are rejected. That right applies to “all ‘critical’ stages of the criminal proceedings.”
..As a general rule, defense counsel has the duty to communicate formal prosecution offers to accept a plea on terms and conditions that may be favorable to the accused. Any exceptions to this rule need not be addressed here, for the offer was a formal one with a fixed expiration date.
To show prejudice where a plea offer has lapsed or been rejectedbecause of counsel’s deficient performance, defendants must demonstrate a reasonable probability both that they would have acceptedthe more favorable plea offer had they been afforded effective assistance of counsel and that the plea would have been entered without the prosecution’s canceling it or the trial court’s refusing to accept it,if they had the authority to exercise that discretion under state law.