WASHINGTON -- The Supreme Court opened the door yesterday for two new challenges to the death penalty, one that allows the use of new DNA evidence to contest an old murder conviction and a second that casts doubt on how lethal injections are carried out.
In the decisions, the court made clear again that it views the death penalty as subject to especially close scrutiny.
Support for the death penalty has been shaken by revelations that innocent persons have been condemned to death. And last year, new research suggested lethal injections could cause intense pain, triggering appeals that challenge the procedure in many states.
During the last decade, the Supreme Court and Congress have made it harder for federal judges to reopen capital cases, responding to complaints over seemingly endless hearings.
But yesterday, the court shifted course slightly and announced two exceptions to the rules against reopening death cases in federal court. Both reflect the impact of new science in criminal justice system.
Justice Anthony M. Kennedy delivered both decisions for the court.
With the retirement of Justice Sandra Day O'Connor, he has assumed the center spot when the court is closely split along ideological lines.
For the first time, the court held that DNA evidence which undercuts a defendant's guilt is reason enough for a federal judge to reopen a case.
Twenty years ago, Paul House, a paroled rapist and a newcomer to a Tennessee town, was found guilty of murdering a woman who lived two miles away.
Prosecutors theorized he had tried to rape the victim. A decade later, lawyers learned that a semen stain had come from the victim's husband, not House.
In a 5-to-3 decision, the court said such ``reliable new evidence" was reason enough for a federal judge to reopen his case.
DNA evidence has already freed scores of prisoners, including some who were on death row.
Lawyers for the Innocence Project, which is based in New York, predicted that yesterday's ruling will have a broad impact because it removes a barrier to having some of these cases heard in federal court.
In the second case, the court put states on notice they will have to defend the mix of drugs that are used for lethal injection.
In recent decades, the use of lethal drugs took the place of the electric chair as the standard means of carrying out executions. All states with capital punishment, except Nebraska, call for lethal injection as the execution method.
Last year, the Lancet, the British medical journal, published a study that concluded some executed men may have suffered intense, burning pain as they died. The study said that could happen because they were not given enough anesthetic.
In response to the Lancet study, lawyers from inmates facing execution cited it in last-minute appeals in federal courts and urged judges to act. They argued that these lethal injections, as currently practiced, amounted to cruel and unusual punishment, a violation of the Eighth Amendment.
In January, the Supreme Court halted the execution of Clarence Hill, the murderer of a Florida police officer, and agreed to hear his assertion that the lethal injection procedure the state had intended to use was unconstitutional.
Yesterday, the court ruled unanimously for Hill, but said only that a federal judge should hear his claim. The justices stressed that Hill was not contesting his guilt or his death sentence.
Legal experts said the decision would have a temporary impact. ``This will be a speed bump," said Eric M. Freedman, a law professor at Hofstra University.