Lester Bower in an undated picture released by the Texas Department of Criminal Justice. (Reuters)

UPDATE: Texas executed Bower on Wednesday evening. A state official said that Bower was pronounced dead at 6:36 p.m. local time. Bower was the 15th inmate executed in the United States this year, and more than half of those executions took place in Texas. 

On Wednesday, the state of Texas plans to do something it has been trying to do for decades: Execute Lester Bower.

Bower, 67, has spent nearly half of his life on death row. He was convicted of shooting and killing a man while attempting to steal an ultralight plane that the man was trying to sell in 1983, and then fatally shooting three other men when they unexpectedly showed up at the aircraft hangar, according to the Texas Department of Criminal Justice.

His attorneys argue that Bower was convicted due to circumstantial evidence, and that since his trial, new evidence has emerged undermining the prosecution that sent Bower to death row.

“This is a case in which there is a significant lingering doubt regarding guilt or innocence,” his attorneys argued in a filing last week.

The U.S. Supreme Court on Wednesday afternoon denied his requests for a stay of execution, with the full court rejecting his requests without explanation.

Attorneys for Bower also pointed to other arguments that they hope will keep Bower from the execution chamber, including an issue involving his sentencing. Bower’s execution had been scheduled for Feb. 10, but the week before, the Supreme Court granted his request for a stay while it considered whether to hear his case. In March, the justices decided against hearing the appeal and lifted the stay.

[Nebraska just became the 19th state to abolish the death penalty]

After the court said it would not hear the case, Justice Stephen Breyer wrote in a dissent that the court should hear it because of the sentencing issue. When Bower was convicted, the jury helping decide his sentence did not consider potentially mitigating evidence, something the Supreme Court later said was unconstitutional. As a result, Beyer says this should allow for a new sentencing hearing for Bower.

“I recognize that we do not often intervene only to correct a case-specific legal error,” Breyer wrote in the dissent, which was joined by two other justices, Ruth Bader Ginsburg and Sonia Sotomayor. “But the error here is glaring, and its consequence may well be death.”

Bower’s attorneys have also argued that his long stint on death row should help him avoid lethal injection. The average death row inmate in Texas spends a decade there, while death row inmates nationwide have spent an average of 14 years under their sentences.

Bower, earlier this year. (Michael Graczyk/AP)

If Bower is executed, he will be the oldest inmate executed in Texas history. And his 30 years on death row will make him the second-longest-serving inmate put to death by Texas, trailing only David Lee Powell, executed in 2010 after 31 years on death row for shooting and killing a police officer during a traffic stop.

Texas state officials have argued against granting Bower a reprieve, saying that because Bower has been fighting his looming execution in the courts for so long, his lengthy tenure on death row “is purely of his own making.”

“Bower’s claims are nothing more than a meritless attempt to postpone his execution,” the office of Ken Paxton, attorney general of Texas, said in a filing to the Supreme Court. “The families of the victims of Bower’s quadruple murder have been waiting to see Bower’s sentence carried out for over thirty years now.”

In another filing, Paxton’s office wrote: “Bower already had his bite at the apple, and a second bite is not warranted.”

[Americans support the death penalty, are pretty sure innocent people can get put to death]

Nationwide, there were nearly 3,000 inmates on death row at the end of 2013, according to federal statistics. One in eight had spent at least a quarter of a century on death row.

The country’s death row population has shrunk considerably since 2000, with more people leaving death row than arriving each year, but not because more people were being executed. In fact, the United States has been carrying out fewer and fewer executions since that time, reaching a 20-year low last year.

Consider 2013. There were 115 inmates removed from state and federal death rows that year. Most left death row because a court overturned their sentences or convictions, while almost as many inmates died from other causes (31) as were executed (39).

A federal judge in California last year called that state’s death penalty system unconstitutional and “completely dysfunctional.” U.S. District Judge Cormac J. Carney wrote in a stern order that the state’s system is so riddled with delays that death sentences are “actually carried out against only a trivial few of those sentenced to death.”

In that case, Carney was writing about an inmate sentenced to death two decades earlier. Carney said that executing the inmate so long after his sentencing violated the Eighth Amendment’s ban against cruel and unusual punishment.

California and Texas, along with Florida, have the largest death row populations in the country.

This post was first published on June 2. It has been updated with news that the Supreme Court rejected the stay requests.