CASE COMMENT ::The consideration of mitigating evidence-evidence that weighs against the imposition of the death penalty in a capital defendant’s individual case-has been deemed a “constitutionally indispensable” feature of a valid capital sentencing scheme. And yet, Jeffrey Landrigan, like many capital defendants, was sentenced to death without the consideration of any mitigating evidence whatsoever. Landrigan’s trial counsel failed to uncover substantial evidence of Landrigan’s history of severe physical and sexual abuse as a child, and of the possible biological effects of his mother’s alcohol and drug abuse. Every member of the Ninth Circuit en banc panel considering his case deemed his counsel’s performance to be objectively unreasonable. But the Supreme Court, by a 5-4 vote, denied Landrigan habeas relief, on the grounds that he had “waived” his right to present mitigating evidence. In so doing, the Court ignored longstanding precedent holding that a criminal defendant’s waiver of a constitutionally protected trial right can only be valid if the record affirmatively establishes that the defendant made his waiver with an understanding of the nature of the right at stake and of the consequences of waiving it. Moreover, the Court’s decision in Landrigan raises substantial concerns under the Eighth Amendment, increasing the likelihood that capital defendants in future cases will be sentenced without the presentation of mitigating evidence, thus undermining the reliability and integrity of capital sentencing. Just as an ordinary criminal defendant must be informed of and aware of the consequences if he opts to waive the right to trial itself, so too should similar safeguards attach where a capital defendant purportedly waives his right to present a mitigation case during sentencing proceedings, which are, in essence, a second trial. Any other result would be strangely incongruous, rendering the right to present mitigating evidence as the lone trial right of criminal defendants that is not subject to a “knowing and voluntary” requirement. Given the confusion amongst the lower courts on this issue, the establishment of a knowing and voluntary requirement in this context makes sense not only from a perspective of judicial economy, but also to minimize the number of capital defendants sentenced to death without presenting a case in mitigation, a phenomenon that is abhorrent to the Eighth Amendment’s proscription against the arbitrary imposition of the death penalty.