Potential jurors in murder cases typically face a barrage of questions from attorneys -- for example, can they put aside biases, or do they know anyone connected to the case?
But there's a question unique to death penalty cases -- could you impose the death penalty? If you couldn't under any circumstances, you're excused from the jury. If you could, you're death qualified to sit on the jury.
Thirty-seven states and the federal court system allow capital punishment. Oregon prosecutor Joshua Marquis has handled about a dozen cases that were eligible for the death penalty. He's also served as co-chairman of the National District Attorneys Association's Capital Litigation.
Marquis says the question simply comes down to whether a person can apply the law in jurisdictions that impose the death penalty.
"It's a question of whether or not your moral or religious or philosophical beliefs are so great that they're going to overrule your ability to be fair on the law," says Marquis.
On the other hand, jurors who say they would always impose the death penalty after a guilty verdict are barred from sitting on the jury too. But that doesn't always happen, according to John Blume, a law professor and head of Cornell University's Death Penalty Project.
Blume says Cornell interviewed hundreds of jurors who sat in death penalty cases in about 15 states. The research found that many of the jurors who were death qualified imposed the death penalty automatically, and should have been excused.
It's a question of whether or not your moral or religious or philosophical beliefs are so great that they're going to overrule your ability to be fair on the law.Oregon prosecutor Joshua Marquis
"Somehow people are getting through who can't follow the law and are very predisposed to give death, if not automatically predisposed to give death. omehow (they still make it) through this process," Blume says.
Blume says it's unclear exactly why those who favor a mandatory death penalty are still getting on juries.
Defense attorneys have also criticized the death qualified requirement because they say it stacks the jury with jurors who are more likely to convict.
Beth Bochnak has worked on behalf of more than 25 defendants in capital cases as a jury consultant as part of the National Jury Project. Jury consultants help attorneys decide which potential jurors would be supportive of their side of the case.
Bochnak says the problem with the death qualified requirement is that it jumps ahead to the penalty phase of a case.
"It encourages jurors to look at the first part of the trial, the guilt/innocence part, as the prelude to the death penalty. So guilt is almost assumed," says Bochnak. "I think it's extremely hard to get a not guilty verdict in a capital case because people are all oriented toward thinking, 'Pretty soon we're going to get to the next part.'"
After conviction, a death penalty jury moves into a second phase. Jurors hear arguments on whether the crime was so heinous that the defendant deserves death, or whether there were mitigating factors that warrant life in prison like severe child abuse.
Bochnak says it would be fairer to have two separate juries in one case -- the first decides guilt or innocence, and the second decides whether to execute the defendant. That way the first jury can focus solely on whether the defendant is guilty rather than anticipating the death penalty phase.
Prosecutor Joshua Marquis says two separate juries for one case is unworkable because it would mean bringing another jury up to speed on the facts.
"In trying cases, they are long and hard enough. You would have to tell the penalty-phase jury all of the evidence you told the guilt-phase jury. So you're talking about doubling the cost, time, length of trial, and it simply makes very little sense," Marquis says.
The U.S. Supreme Court upheld the death qualification requirement in a case 20 years ago, when an Arkansas man argued that a jury composed solely of members who could impose the death penalty violated his constitutional right to an impartial jury.
Writing for the majority, Justice William Rehnquist disagreed. He said the constitutional standard only requires that juries represent a cross-section of the community and can apply the law to the facts of the case.