In the case of Leroy L. Young, et al. v. Ernest Eugene Harper in 1996, the U.S Supreme Court addressed whether Ohio's parole guidelines violated ex post facto laws by retroactively applying harsher standards to inmates who committed their crimes before the new rules were implemented. The court ruled that Ohio’s revised parole policies did indeed violate ex post facto laws as they created a significant risk of prolonging an inmate's incarceration time beyond what would have been permissible under previous guidelines at the time of their offense and sentencing. This decision was based on principles protecting individuals from retrospective legislation which imposes or increases punishments for acts committed prior to enactment of such law.

In the dissenting opinion for Leroy L. Young, et al. v. Ernest Eugene Harper, Justice Clarence Thomas argued that the majority's decision was not based on a correct interpretation of the Constitution or precedent cases but rather on their own policy preferences regarding parole eligibility and release procedures in Ohio. He contended that there is no constitutional right to be considered for discretionary parole and thus disagreed with the majority’s view that due process requires states to apply changes benefiting inmates retroactively. Furthermore, he criticized the Court's reliance on an equal protection argument as it failed to recognize legitimate state interests in treating different classes of prisoners differently based upon when they committed their crimes.