May a court assessing Strickland prejudice dismiss the significance of evidence of brain damage, on the ground that it makes only a 'limited additional contribution' compared to other mitigation evidence, as the Ninth Circuit has held, or does evidence of brain damage have uniquely mitigating weight, as four other circuits have held?

QUESTION PRESENTED Trial counsel in this capital case knew that the defendant’s mother had consumed alcohol while pregnant. Despite recognizing the need to investigate whether the defendant suffered from Fetal Alcohol Spectrum Disorder, and to consult an expert on that disability, trial counsel did neither. Federal habeas counsel subsequently retained such an expert, who concluded that Floyd met the criterion for a diagnosis of FASD and had suffered organic brain damage as a result of his mother’s use of alcohol during her pregnancy. The court of appeals rejected the defendant’s claim of ineffective assistance of counsel solely on the ground that the asserted ineffectiveness was not prejudicial; the appellate court did not address whether trial counsel was ineffective, or whether this habeas claim was affected by AEDPA. The question presented is: May a court assessing Strickland prejudice dismiss the significance of evidence of brain damage, on the ground that it makes only a “limited additional contribution” compared to other mitigation evidence, as the Ninth Circuit has held, or does evidence of brain damage have uniquely mitigating weight, as four other circuits have held?* '*The same question is presented in Anderson v. Payne,No.19°8105. i