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Legal experts say the plea bargain with the Green River Killer (search) raises a thorny question: If the state of Washington is not going to execute someone who has confessed to murdering 48 people, how can it ever again put anyone to death?

It is a question of simple fairness: Under state law, the Washington state Supreme Court is required to review every death sentence handed out, and must consider whether the sentence "is excessive or disproportionate to the penalty imposed in similar cases, considering both the crime and the defendant."

Some lawyers say a death sentence for someone who killed one or two people could well be considered "disproportionate" when compared to what Gary Leon Ridgway (search) got.

"People are concerned that if they don't seek the death penalty in the Ridgway case, it would not be permissible to seek it in any case," said University of Washington criminal law professor John Junker. "How do you find anybody who's done worse than he's done?"

That logic may have national implications.

When the U.S. Supreme Court cleared the way for the death penalty in 1976, it was with the understanding states would ensure it was being applied proportionally, said Richard Dieter, executive director of the Washington, D.C.-based Death Penalty Information Center (search).

In theory at least, someone on death row for a murder in Texas could appeal on the grounds it's unfair to execute him while Ridgway was spared.

"This is a glaring example that may even interest the Supreme Court," Dieter said Wednesday. "There will be appeals, and there may well be a review about the whole country's use of the death penalty. If it can't be applied more uniformly or predictably, maybe we shouldn't have it."

Ridgway, a 54-year-old truck painter, pleaded guilty Wednesday to the murders of 48 women in a deal that spares him from the death penalty for those slayings and assures him a sentence of life in prison without parole.

Washington state has executed four people since the resumption of capital punishment. Washington is one of 38 states with the death penalty.

Initially, King County Prosecutor Norm Maleng vowed he would not bargain with Ridgway over the death penalty, precisely for the reason of proportionality. It would be unfair not to apply it to the Green River Killer when the state has executed far less prolific killers, he said.

On Wednesday, Maleng said Ridgway's case wouldn't prevent the state from using the death penalty because the case is so unusual it can't be compared with any other. "It will meet any so-called proportionality review," he said.

But anti-death-penalty activists, defense lawyers and some legal scholars questioned the prosecutor's reasoning. "If you have stories to tell, you get a plea bargain," Dieter said. "If you don't, you get the death penalty."

Roger Hunko, president of the Washington Association of Criminal Defense Lawyers, said another serial killer in Washington state is already testing the proportionality argument.

Three years ago, Robert Yates confessed in Spokane County to killing 13 people, but he was then tried, convicted and sentenced to death for killing two other people in Pierce County.

Hunko, who represented Yates at trial, said Yates will argue on appeal: If Yates did not get the death penalty for 13 murders in one county, how can he get it for two in another?