The Supreme Court ruled unanimously Monday that the nation's death row inmates can file last-minute challenges to lethal injection after they've exhausted their regular appeals.

The court's ruling leaves unanswered, however, broader questions about the chemicals used in lethal injections around the country and whether they cause excruciating pain.

The ruling sets the stage for a nationwide legal battle over that subject, with the country's 3,300 death row inmates armed with a new tool to contest how they are put to death. Justices have never ruled on the constitutionality of a specific type of execution. A constitutional showdown over lethal injection might be the next big death penalty case.

Click here to read the opinion (pdf).

The winner in Monday's decision was Florida death row inmate Clarence Hill, who was strapped to a gurney with lines running into his arms to deliver the drugs when the Supreme Court in January intervened and blocked the execution.

Justice Anthony M. Kennedy, writing for the court, said that while Hill and other inmates can file special appeals, they will not be always entitled to delays in their executions.

"Both the state and the victims of crime have an important interest in the timely enforcement of a sentence," he wrote.

Hill, convicted of killing a police officer, had run out of regular appeals so he went to court using a civil rights law claiming that his constitutional rights would be violated by Florida's lethal injection drug protocol. The court's decision renews his bid to have Florida change its chemical combination.

The decision is setback for Florida and other states that will have to defend more last-minute filings from inmates. More than two dozen states had filed arguments at the court seeking the opposite outcome. They said dragged-out appeals jeopardize justice for victims' families.

Lethal injection is the main method used by every state that has capital punishment except Nebraska. Nebraska still has the electric chair, although that, too, is being contested.

Kennedy said that Hill is not claiming that he cannot be executed, only that he should not be forced into a painful execution.

"Hill's challenge appears to leave the state free to use an alternative lethal injection procedure," Kennedy wrote.