Thurgood Marshall

“ Even if I did not take this view, I would grant the petition to decide whether a court's failure either to inform a capital sentencing jury that it must consider mitigating evidence or to explain the concept of mitigation undermines a capital defendant's right to have the jury "consider and give effect to any mitigating evidence relevant to a defendant's background and character or the circumstances of the crime." ”

“ The imposition of the death penalty should not be contingent on a particular jury's unguided understanding of a legal term of art. When a trial court refuses to give content to the words on which a defendant's life depends, the subsequent sentence is arbitrary and capricious. ”

“ Even if the juries were aware of their obligation to consider mitigating evidence, the instructions provided absolutely no guidance on what constitutes relevant mitigating evidence or how the juries should have considered such evidence. "Mitigating evidence" is a term of art, with a constitutional meaning that is unlikely to be apparent to a lay jury. ”