Darrell Payne. Ethan Windom. Joseph Duncan. John Delling.

Those are some names of infamous murderers known to Treasure Valley residents, whose attorneys at one time or another said were not treated fairly by an Idaho justice system that does not allow for a traditional insanity defense.

Payne is on Idaho’s death row. Delling and Windom are serving life prison sentences. Duncan has three federal death penalty sentences and is being held in a federal prison in Seattle.

The defense argument is pretty simple: Those men were so severely mentally ill when they committed their crimes that they should have been allowed to use that as a defense in a criminal case. They say Idaho’s lack of insanity defense is unconstitutional.

The Idaho Supreme Court has rejected the last six appeals on the issue, stretching back to 1990 and including a request by Delling’s lawyers in 2011.

The U.S. Supreme Court announced last month it would not hear Delling’s appeal, effectively ending his criminal case and reinforcing Idaho’s decision — along with Montana, Utah, and Kansas — not to allow a traditional insanity defense.

For now. That hasn’t stopped defense lawyers from filing appeals in the past. And they will file appeals again. But with Delling’s appeal shot down, it’s unclear when attorneys in Idaho will summon the will to try once again.

Delling, apparently driven by internal voices to kill two men and injure a third on a multi-state spree, was considered the best chance to get the U.S. Supreme Court to debate the Idaho insanity defense. Delling’s lawyers, police, prosecutors and 4th District Judge Deborah Bail all agreed that Delling’s mental illness led him to become a killer. The lack of an “insanity defense” became the defining issue of his case,

”We won’t get a better case than we did with Delling,” said Sarah Thomas, the Idaho appellate state defender.

One encouraging thing for advocates is that justices Stephen Breyer, Ruth Bader Ginsburg and Sonia Sotomayor said they would have heard the case. That was one judge short of the four votes required for the court to hear the case. Breyer even wrote a public dissent, saying justices should consider whether Idaho’s modification of the insanity defense is consistent with the 14th Amendment’s promise of “due process.”

But the discouraging thing is that advocates have to wait for a new justice to add a fourth vote.

“I guess it’s encouraging that we are on their radar, and they might consider it someday,” Thomas said. “I don’t think our (Idaho) Supreme Court will ever overrule this. They have denied it too many times already.”

FEW APPEALS

For those reasons, Thomas is pretty sure her office won’t be filing any “writ of certiorari” appeals about the insanity defense soon. That process requires an incredible amount of work and needs to be a case where there is significant and compelling evidence that the convicted person — like Delling — is suffering from a deep and profound mental illness.

Of the six cases rejected by Idaho’s top court, two were deemed strong enough for defense attorneys to appeal to the U.S. Supreme Court. In addition to Delling, the other was the 1991 Mitchell Odiaga murder case in Blaine County. Odiaga was a U.S. postal worker from Boise who shot two people on the streets of Hailey.

Jeffrey Fisher, a Stanford Law School professor specializing in the Supreme Court who worked on the Delling case, said he could understand why Idaho lawyers may be discouraged. But he sees progress.

“It is unfortunate — we would have loved to have the court take the (Delling) case, but in the past, we’ve gone to a place where petitions have fallen on deaf ears,” Fisher said. “Now, we have three justices saying we should have a serious review of what Idaho is doing, and that is a significant step forward. A fair reading of (Breyer’s dissent) is that they have real misgivings about Idaho law.”

Fisher said he, like his Idaho counterparts, feels re-establishing the insanity defense is a matter of basic fairness.

“I am persuaded from the extraordinarily deep history, across centuries of Anglo-American law, that someone who is truly incapable of knowing right from wrong should be allowed” the insanity defense, he said. “I don’t think states are entitled to abandon that principle.”

A ROLE IN SENTENCING

The Idaho Legislature banned the insanity defense amid the national outcry over the acquittal of would-be assassin John Hinckley Jr., who shot President Ronald Reagan in 1981.

Boise defense attorney David Leroy, who was Idaho’s attorney general when the state did away with the insanity defense in 1982, explained the rationale for the change in 2009.

“Idaho eliminated the insanity defense in the old English common law sense. That is the argument that the defendant was out of touch with reality and didn’t understand the consequences of their actions,” Leroy said. “We determined in 1982 that a better test (for insanity) would be to ask the jury to examine the specific mental state of the defendant at the time of the crime for the presence or absence of a specific element.

“Since the prosecutor must prove all elements of the crime to convict, the absence of such proof as to a mental element still constitutes a defense.”

Lawyers in Idaho trials can still offer evidence of mental illness for mitigation purposes, but not as a defense. And it is a factor in sentencing: Analysis of Delling’s mental illness was a major part of the presentence reports and his sentencing hearing.

“In the absence of an insanity defense, Delling is still able to present a defense; it just takes a different form,” the Idaho Supreme Court said in denying Delling’s appeal in 2011. “If the state cannot prove criminal intent beyond a reasonable doubt, a defendant, sane or not, will be found not guilty.”

In his dissent, Breyer pointed out that Idaho’s standard for the insanity defense differs from other states: Idaho permits the conviction of someone “who knew what he was doing but had no capacity to understand it was wrong.”

Fisher said that uncertainty over what the insanity defense allows and doesn’t allow in Idaho is an encouraging sign for the next challenge. Whenever that may be.

Patrick Orr: 377-6219, Twitter: @IDS_Orr