In the United States v. Angela Ruiz case of 2001, the Supreme Court ruled that a defendant who pleads guilty under a plea agreement does not have an automatic right to receive material impeachment information before making their decision. The court held that there is no constitutional requirement for prosecutors to disclose such information prior to entering into a fast-track plea bargain. This ruling was based on the premise that defendants waive many rights when they plead guilty and this includes some discovery rights as well. Therefore, it concluded that while full disclosure might be beneficial in theory, it's not constitutionally required in practice during pre-plea negotiations.

In the dissenting opinion for United States v. Angela Ruiz, Justice Scalia argued that the majority's decision effectively allowed prosecutors to withhold information about potential defenses from defendants during plea bargaining. He believed this was a violation of due process rights and fundamentally unfair to defendants who are making critical decisions about their cases based on incomplete information. Furthermore, he pointed out that it is not uncommon for prosecutors to have exculpatory evidence in their possession which they may choose not to disclose before a defendant enters into a plea agreement. This could potentially lead innocent people into pleading guilty because they were unaware of crucial evidence that could prove their innocence or at least cast doubt on their guilt. Thus, Justice Scalia disagreed with the majority's ruling and felt strongly that all relevant material should be disclosed prior to any plea negotiations.