[2] Defense counsel was prohibited from asking potential jury members about their understanding of parole in voir dire.

"[11] Defense counsel repeatedly requested permission to instruct the jury that, because of Mr. Simmons' parole ineligibility, he could never be released from prison.

[13] Justice Blackmun's plurality opinion began by grounding the Court's holding in the Due Process Clause, which requires that no person be executed "'on the basis of information which he had no opportunity to deny or explain.

'"[14] The opinion then detailed the trial court proceedings, and the "grievous misperception" created by the emphasis on Mr. Simmons' future dangerousness and the absence of an instruction regarding his parole ineligibility.

[15] In particular, the plurality noted the defense's repeated requests – and the court's refusals – to instruct the jury on Mr. Simmons' parole status.

"[5] The plurality pointed to several studies[16][17][18][19] which indicated that jurors commonly misunderstood the meaning of the term "life imprisonment" to permit early release.

[5] Of course, the plurality noted, the State was permitted to emphasize future dangerousness as a valid factor for the jury to consider in sentencing.

[22] In addition to the due process clause, Justice Souter wrote, the Eighth Amendment imposed "a straightforward duty on the court" to instruct juries on the meaning of a capital defendants' parole eligibility.

[23] The concurrence also noted that the court (as opposed to the defense counsel) should have provided the parole ineligibility information, so as to ensure that the jury understood it to be a binding statement of law.

[28] And the plurality was not based on the Court's precedent, the dissent argued, because those cases involved an emphasis on future dangerousness that was absent from the Simmons record.

As the Simmons plurality opinion noted, most states were already providing similar instructions for capital defendants facing life without parole or execution.