In the United States v. Agurs case of 1975, the Supreme Court examined whether a prosecutor's failure to disclose exculpatory evidence violated the defendant's due process rights under Brady v. Maryland (1963). The defendant, Agurs, was convicted of murder and later discovered that the prosecution had withheld information about the victim’s criminal record which could have been used in his defense. He appealed for a new trial on these grounds but both district and appellate courts denied this request. Upon reaching Supreme Court review, it held that while prosecutors must disclose exculpatory evidence if requested by defendants or if it is materially favorable to them even without such requests; they are not obligated to provide all potentially useful information unless specifically asked for by defendants' counsel or when withholding would be fundamentally unfair leading to miscarriage of justice. In this particular case though, since neither condition applied as per majority opinion led by Justice Marshall - no specific request was made nor did non-disclosure lead to fundamentally unfair trial - hence Agur’s conviction stood.

In the dissenting opinion for United States v. Agurs, Justice Byron White argued that the majority's decision to create a new standard of materiality was unnecessary and potentially harmful. He contended that existing precedents already provided adequate guidance on how to handle undisclosed evidence in criminal trials. Furthermore, he expressed concern about the potential implications of this new rule, suggesting it could lead to an increase in appeals based on claims of withheld evidence and put undue pressure on prosecutors who must decide what information is "material" enough to disclose. Justice White also disagreed with the majority's view that there should be different standards for cases where defense counsel specifically requested certain information versus those where no such request was made; he believed this distinction would only serve to confuse matters further.