In the case of Joseph Libretti v. United States, 1995, the U.S. Supreme Court ruled that a defendant who voluntarily and knowingly pleads guilty to a crime forfeits their right to challenge their sentence on appeal if they did not previously reserve this right during plea negotiations. The court held that such waivers are valid under federal law as long as they are made knowingly and voluntarily by the defendant. This decision came after Joseph Libretti pleaded guilty to several drug-related charges without reserving his right to appeal his sentence in future proceedings. After receiving multiple life sentences plus additional years, he attempted to appeal but was denied due to his failure to reserve this right during plea bargaining.

In the dissenting opinion for Joseph Libretti v. United States, it was argued that the majority's decision undermined a fundamental principle of criminal law: that defendants must knowingly and voluntarily waive their rights. The dissenting justices believed that this principle should apply to sentencing as well as to guilt or innocence. They pointed out inconsistencies in how waivers were treated in different contexts, arguing for a more uniform approach. Furthermore, they expressed concern about potential abuses if prosecutors could pressure defendants into waiving their rights without fully understanding what they were giving up. In conclusion, while acknowledging the need for efficiency in plea bargaining and sentencing procedures, these justices emphasized the importance of protecting individual rights within this process.