In the case of David Bobby, Warden v. Robert J. Van Hook (2009), the US Supreme Court overturned a decision by the Sixth Circuit Court of Appeals that had granted habeas corpus relief to death row inmate Robert J. Van Hook on grounds that his counsel provided ineffective assistance during sentencing phase of his trial for murder in 1985. The Supreme Court ruled unanimously that the appeals court misapplied federal law and failed to give due deference to state court decisions, thereby exceeding its authority under Antiterrorism and Effective Death Penalty Act (AEDPA) which limits federal courts' power to grant habeas corpus relief unless state courts unreasonably apply clearly established Federal law or make unreasonable determinations based on evidence presented in State proceedings. The high court found no reason to believe Ohio's highest court acted unreasonably when it concluded defense attorneys met professional standards at time despite not conducting extensive background investigation into potential mitigating factors before sentencing.

In the case of David Bobby, Warden v. Robert J. Van Hook, Justice Alito dissented from the majority opinion that granted habeas corpus relief to Van Hook on grounds of ineffective assistance of counsel during his sentencing phase for a 1985 murder conviction. Alito argued that the defense counsel's performance was not deficient under prevailing professional norms at the time and thus did not meet Strickland’s standard for ineffectiveness. He pointed out that while American Bar Association (ABA) guidelines were cited by majority as a measure for effective representation, they should be used only as general guidance rather than strict standards against which all attorney conduct is judged. Furthermore, he noted these ABA guidelines came into effect years after trial in question and hence could not represent contemporary standards applicable then.