In the case of Hicks v. Oklahoma, 1979, the defendant was convicted on three counts of distributing heroin and sentenced to forty years imprisonment for each count under an Oklahoma statute that mandated a minimum sentence of forty years for defendants with two or more felony convictions. However, during his appeal process, this law was declared unconstitutional by the state's Supreme Court in another case. Despite this ruling, Hicks' sentence wasn't reduced as it would have been if he were sentenced after the law had been struck down. The U.S Supreme Court ruled that even though states have discretion over sentencing within constitutionally prescribed limits; they must exercise their power through standards not arbitrary or discriminatory - which is a fundamental element of due process required by Fourteenth Amendment. Therefore denying Hicks re-sentencing based on now-unconstitutional law violated his right to due process and equal protection under Fourteenth Amendment.

In the dissenting opinion for Hicks v. Oklahoma, Justice Rehnquist argued that the Supreme Court should not have taken up this case as it did not present a substantial federal question. He believed that there was no violation of due process in Hicks' sentencing by an Oklahoma court under a habitual offender statute later declared unconstitutional. The justice pointed out that even if the sentence had been imposed under an alternative valid statute, it would still be within permissible limits and thus does not constitute cruel or unusual punishment. Furthermore, he noted that any error made by state courts in applying their laws does not automatically equate to a denial of fundamental fairness required by due process clause unless it offends some principle of justice so deeply rooted in traditions and conscience of our people as to be ranked as fundamental.