In the case of Paul Delo, Superintendent, Potosi Correctional Center v. Walter J. Blair in 1992, the U.S Supreme Court addressed whether a Missouri state prisoner's federal habeas corpus petition was procedurally barred due to his failure to raise an objection at trial or on direct appeal regarding jury instructions about mitigating circumstances in capital sentencing proceedings. The court ruled that Blair had not demonstrated cause for his procedural default and therefore could not proceed with his claim. This decision upheld the principle that defendants must adhere strictly to all stages of legal procedure and cannot bypass them without showing good reason.

In the dissenting opinion for Paul Delo, Superintendent, Potosi Correctional Center v. Walter J. Blair (1992), Justice Blackmun argued that the majority's decision to deny Blair a stay of execution was inconsistent with previous rulings and violated his Eighth Amendment rights against cruel and unusual punishment. He contended that the Court had previously held in Ford v. Wainwright that it is unconstitutional to execute someone who lacks mental competency, yet they were now allowing Blair’s execution despite evidence suggesting he may be mentally incompetent due to schizophrenia. Furthermore, Blackmun criticized Missouri's procedures for determining competency as inadequate because they did not provide an opportunity for a hearing or judicial determination on this matter before carrying out an execution.