On June 6, after closing arguments concluded in the penalty phase of the federal murder trial of Naeem Williams in Honolulu, Steven Mellin, the lead prosecutor in this case, told me he had "just wasted six months of my life" in trial and trial preparations.

Mellin said he was "certain" the jury would not sentence Williams to death.

"No way," he emphasized. "There is no way this jury will return a sentence of death."

Mellin was right. On June 27, the jury deadlocked 8-4 in favor of capital punishment for the former soldier who was convicted of killing his 5-year-old daughter Talia in 2005. By law, the jury’s non-unanimous decision means Williams will be sentenced to life in prison without the possibility of parole.

Three federal prosecutors have said they are pleased with this outcome. Florence Nakakuni, the U.S. attorney for the District of Hawaii, said life without parole "is an appropriate sentence." Darren Ching, an assistant U.S. attorney in Hawaii, said "justice has been served." And Mellin said life without the possibility of release is "a very satisfying result in this case."

The good cheer of these prosecutors is more than a little puzzling. Williams’ capital trial lasted more than three months, cost millions of dollars more than a plea bargain or non-capital trial would have, required the jury to attend 42 trial sessions in addition to seven days of deliberation — and resulted in the same sentence that Williams had repeatedly offered to accept in plea negotiations with prosecutors over the past nine years.

From the start, Williams’ case had too many weaknesses to warrant the huge investment of resources that is normal in seeking a sentence of death. Among other problems for prosecutors, Williams had no prior record of violence, and in 2006 his wife Delilah (Talia’s stepmother) received a sweetheart deal of 20 years imprisonment through a plea bargain that prosecutors agreed to before they realized that her abuse of Talia was, in many respects, as harmful and heinous as that of Naeem.

The biggest puzzle about this prosecution is why U.S. Attorney General Eric Holder insisted on seeking a sentence of death despite the serious reservations of prosecutors who were closer to the case, and despite repeated offers by the defense to have Williams plead guilty in exchange for a life sentence.

This question about Holder raises a parallel puzzle about the man who appointed him, former Hawaii resident and President Barack Obama. Why does Obama encourage and condone a federal prosecution policy that regularly seeks sentences of death in jurisdictions that have abolished capital punishment, especially when there have been only three federal executions in the U.S. in the past 50 years — and none at all on Obama’s watch?

In the Williams case, Holder inherited a decision to seek a sentence of death from previous attorneys general who were appointed by President George W. Bush. Holder could have changed that decision — and he should have.

Holder’s experiment in Hawaii failed, and so has America’s experiment with the death penalty more generally. Numerous studies have shown that the practice of capital punishment remains fraught with arbitrariness, discrimination and mistake. Two-thirds of the nations in the world have abolished the death penalty, and the Territory of Hawaii abandoned it more than half a century ago.

Why do leaders like Holder and Obama continue to coddle delusions about this dysfunctional institution?