In the case of Machibroda v. United States, 1961, the petitioner, Steve Machibroda was convicted for bank robbery and sentenced to 25 years in prison. He later filed a motion under federal law claiming that his plea of guilty had been induced by promises made by an Assistant United States Attorney and an FBI agent who allegedly assured him he would receive a lesser sentence if he pleaded guilty. The District Court denied his motion without hearing any evidence or conducting any inquiry into these allegations. The Supreme Court held that this denial was error as it violated due process rights guaranteed under the Fifth Amendment of the Constitution. The court ruled that when such serious claims are raised about voluntary confessions or pleas influenced by promises from government officials, they must be thoroughly investigated before being dismissed outrightly. Thus, even though there may not have been substantial proof supporting Machibroda's claims at face value, dismissing them without proper investigation constituted a violation of constitutional rights.

In the dissenting opinion for Machibroda v. United States, Justice Clark argued that the petitioner had not met his burden of proof in demonstrating a violation of due process rights. He contended that there was no evidence to support Machibroda's claim that he was coerced into pleading guilty by false promises made by an Assistant U.S Attorney and FBI agents. The justice also pointed out inconsistencies in Machibroda's allegations, such as claiming he pleaded guilty under duress while simultaneously stating he did so voluntarily before the court during his plea hearing. Furthermore, Justice Clark expressed concern about setting a precedent where defendants could easily challenge their convictions based on unsubstantiated claims of coercion or misconduct by law enforcement officials without any corroborating evidence.