The Court held that the prosecutor breached the plea agreement by introducing evidence that was not otherwise before the court in order to signal the defendant deserved incarceration rather than probation. Part of the reasoning to justify the holding was supported by the United States Supreme Court's decision in Santobello v. New York and the Iowa Supreme Court's decision in State v. Bearse (Iowa 2008). It's reasoning was based upon the principle of encouraging integrity in the plea bargaining procedures and public confidence in the fair administration of justice. When a prosecutor does not honor the terms of the plea agreement, the public's confidence in the criminal justice system is undermined.
Moreover, plea agreements require defendants to relinquish fundamental rights. As such, prosecutors are held to high standards in terms of both the promise and the performance with respect to plea agreements, and that any such violation would result in the reversal of the conviction or vacation of the sentence. Prosecutors must do more than simply recite the plea recommendation; rather, prosecutors must indicate to the court that the recommended sentence is supported by the State and worthy of the court's acceptance.
In Lopez, when the prosecutor introduced evidence at the sentencing hearing, it in effect undermined its sentencing recommendation. The Court determined because it undermined its own sentencing recommendation, it did not honor the terms of the plea agreement. Therefore, the Iowa Supreme Court allowed the defendant a new sentencing hearing with a different judge. State v. Lopez, 2015 WL 7890031 (Iowa 2015).
The main takeaway from this case is that if the prosecutor makes a plea agreement with a defendant, then the prosecutor has a duty to honor that plea agreement.