SAN FRANCISCO -- The state's postponement of an execution because no medical professional would take part amounts to a moratorium on capital punishment in California, home to the largest death row, and could have implications for other states that use lethal injection.

Michael Morales, 46, was scheduled to die Tuesday by lethal injection for torturing, raping and murdering a 17-year-old girl 25 years ago. But officials at San Quentin State Prison couldn't meet the demands of a federal judge who ordered licensed medical personnel to take part in the execution. There were no takers and it was called off.

The reprieve meant California, with 650 condemned inmates, awoke Wednesday without a viable death penalty for the first time since 1977, when lawmakers restored capital punishment after a court-ordered hiatus.

The case may eventually place the lethal injection question before the U.S. Supreme Court. Thirty-seven of the 38 states with capital punishment use a procedure that is similar to California's.

Although the high court has never declared any method of execution unconstitutionally cruel and unusual, it is weighing whether inmates can make such challenges on the eve of their executions.

Last week's ruling by U.S. District Judge Jeremy Fogel shifted the debate from the constitutionality of lethal injections to whether medically licensed personnel should play an active role in the execution, something the American Medical Association and other medical groups have long opposed on ethical grounds.

"I have no doubt that every inmate nearing execution will glom onto this," said Kent Scheidegger, director of the Criminal Justice Legal Foundation, a pro-capital punishment group. "But I can't imagine the Supreme Court requiring a state to do something that can't be done."

In past California executions, the intravenous lines were inserted by prison staff trained specifically for that purpose. The drugs were then added by a machine.

Deborah Denno, a Fordham University School of Law professor and expert on lethal injection, said her survey of states with lethal injection found licensed medical experts generally don't take part, other than to pronounce a prisoner dead.

"The states like to keep that a secret," she said.

Natasha Minsker, a capital punishment expert with the American Civil Liberties Union, which opposes the death penalty, believes a prison may be breaking the law by using executioners who don't have proper medical credentials.

"There are limits on practicing medicine with controlled substances," she said. "It appears prison personnel in this are breaking the law because they are not licensed to do this."

Fogel will now hold hearings in May on whether California's method of execution is cruel and unusual punishment. Until that is resolved, neither Morales nor any other California death row inmate are likely to be executed unless licensed personnel step forward.

The next condemned inmate in line, Mitchell Sims, 45, is on death row for killing a Glendale pizza delivery man in 1985. His final appeal rests with the U.S. Supreme Court.

Morales wasn't the first to challenge California's lethal injection procedure on constitutional grounds. Others failed in large part because they didn't include medical records of previous executions.

His attorneys claimed that once a sedative is given the prisoner, he may feel excruciating pain if still conscious when a paralyzing agent is administered. The judge, after reviewing medical logs of six California lethal injections, said he had "substantial questions" about whether inmates were indeed still conscious once the paralyzing agent began coursing through their veins.

Fogel ordered a licensed anesthesiologist to be on hand to ensure that wouldn't happen. In the alternative, he said the prison could use just a sedative, but it would have to be injected by a licensed practitioner, a group that includes doctors, nurses, dentists, paramedics and other medical technicians.

The three-drug protocol used in previous California executions takes about 10 minutes to kill an inmate, while the one-drug method takes 30 minutes or more.

Hours before Morales was to be executed early Tuesday, the anesthesiologists withdrew, citing ethical concerns. The prison then opted for the one-drug method, but couldn't find anybody willing to perform the injection in front of public witnesses at San Quentin.

"This is an issue that is ultimately going to have to be resolved by the Supreme Court," said Richard Dieter, executive director of the Death Penalty Information Center. "Because you're ultimately not likely ever going to have doctors in the execution chamber."

The case is Morales v. Hickman, 06-219.