In the case of Vincent Cullen, Acting Warden v. Scott Lynn Pinholster (2010), the U.S Supreme Court ruled in favor of Cullen, upholding a decision by the Ninth Circuit that had denied habeas corpus relief to Pinholster. The central issue was whether federal courts could consider evidence not presented in state court when reviewing habeas petitions under 28 U.S.C §2254(d)(1). In this context, Pinholster had been convicted for murder and sentenced to death in California state court but later claimed ineffective assistance of counsel during his penalty phase trial. He introduced new mitigating evidence during federal habeas proceedings which were not presented at his original trial or appeal. However, the Supreme Court held that review under §2254(d)(1) is limited to the record before the state court that adjudicated a claim on its merits and does not permit consideration of newly introduced material.

In the dissenting opinion for Vincent Cullen, Acting Warden v. Scott Lynn Pinholster, Justice Sotomayor argued that the majority's decision was overly restrictive and contrary to federal law. She contended that the court should have considered evidence presented during a federal hearing in addition to what was available at the time of state proceedings when deciding whether or not Pinholster had received effective counsel. The majority’s refusal to consider this additional evidence resulted in an incomplete review of his case. Furthermore, she criticized their interpretation of 28 U.S.C §2254(d)(2), arguing it would unjustly limit habeas relief only to those who could prove state courts unreasonably determined facts based on clear and convincing evidence rather than a reasonable doubt standard.