In the United States v. Hayman case of 1951, the Supreme Court examined whether a federal court could suspend a sentence and place an offender on probation for crimes committed prior to his conviction. The defendant, Carlisle B. Hayman, was convicted of mail fraud in 1942 and sentenced to four years imprisonment followed by five years probation. After violating his parole terms in 1947, he was returned to prison where he filed a writ of habeas corpus challenging the legality of his detention based on alleged irregularities during sentencing. The Supreme Court ruled that under Section 2255 (a provision added to federal law in 1948), district courts were authorized only to impose sentences as provided by law at the time offenses were committed; they did not have discretion over post-conviction procedures such as suspending sentences or granting probation unless explicitly allowed by statute. Therefore, since there was no statutory authority allowing suspension or probation for mail fraud when Hayman's crime occurred (prior laws permitting this had been repealed), these aspects of his sentence were invalid and he should be released from custody once serving out any remaining valid portion.

In the dissenting opinion for United States v. Hayman, Justice Robert H. Jackson disagreed with the majority's interpretation of Section 2255 of Title 28 in relation to habeas corpus proceedings. He argued that this section was intended by Congress as a procedural reform to address practical difficulties and not meant to alter substantive rights or principles underlying habeas corpus law. According to him, it should be used only when normal appellate procedures are inadequate or ineffective for testing legality of detention; otherwise, it could undermine finality of judgments and flood courts with frivolous claims from prisoners seeking release on technicalities rather than actual injustice. Furthermore, he contended that the Court had overstepped its bounds by reading into Section 2255 more than what Congress had put there - an authority which belongs solely to legislature.