The U.S. Supreme Court was considering last-minute appeals from a Texas death row inmate scheduled for execution Wednesday, more than two decades after he was convicted in the slayings of his former common-law wife and her brother.

Willie Trottie, who turned 45 on Monday, has acknowledged shooting Barbara Canada, 24, who had a protective order against him, and her brother, Titus Canada, 28, at their parents' home in Houston in 1993. Trottie said the shootings were accidental and in self-defense, and not worthy of a death sentence.

"I'm ready whichever way it goes," Trottie said in a recent interview with The Associated Press. "If God says, 'yes,' I'm ready."

His attorneys appealed to the nation's highest court, arguing that Trottie's lawyers at his 1993 trial were deficient for not addressing his self-defense theory and for failing to produce sufficient testimony about Trottie's abusive childhood with an alcoholic mother.

State attorneys scoffed at the argument, saying Trottie's self-defense claim was absurd and had been rejected in earlier appeals.

But Trottie's attorneys also argued in a separate civil rights lawsuit to the Supreme Court that the dose of pentobarbital scheduled to be used during the lethal injection Wednesday evening was past its effectiveness date. That could subject Trottie to unconstitutional "tortuous" pain, attorney Maurie Levin said.

The state argues that the drug doesn't expire until the end of the month and that tests showed proper potency. They argued the appeal seeking details of the drug was merely another attempt to force prison officials to disclose the compounding pharmacy that provides its execution drugs, something the courts repeatedly have refused to order.

Trottie's lethal injection would be the eighth this year in Texas, and the first in the nation's most active death penalty state since recent executions went awry in Oklahoma and Arizona. Unlike those states, where a drug combination is used for capital punishment, Texas uses a single lethal dose of pentobarbital, a powerful sedative.

Evidence showed that Barbara Canada had called police several times about Trottie and obtained a protective order to keep him away after she said he shot out the tires of her car and threatened to kill her if she didn't return to him.

He called her May 3, 1993, renewing the death threat, then showed up at her parents' house and opened fire with a semi-automatic pistol, according to investigators. Titus Canada also had a gun and wounded Trottie, who then cornered his ex-wife in a bedroom and shot her 11 times before returning to the wounded brother and shooting him twice in the back of the head.

Trottie drove himself to a hospital, where police arrested him.

"There's no doubt I committed this crime," Trottie recently told the AP from prison. "The dispute is the sequence of how it happened."

Trottie said Titus Canada fired first, and that his gun "went off" during a struggle, killing his wife.

Trial prosecutor Johnny Sutton said the claims were "absolutely ridiculous."

"He hunted them down," Sutton said. "They already were worried about him. He was making threats."

Connie Williams, Trottie's lead defense attorney, acknowledged that it was a hard case to defend.

"It was very difficult to defend on the facts," Williams said. "There were eyewitnesses. He went there with a gun ... to do what he thought he had to do."

If carried out, Trottie will be the second death-row inmate executed in the U.S. on Wednesday. Earl Ringo Jr. received a lethal injection just after midnight in Missouri for a 1998 robbery and double murder.

Trottie is among at least 10 convicted killers in Texas with execution dates in the coming months. Next week, an Arlington woman, Lisa Coleman, 38, is set to die for the starvation and torture death of her female roommate's 9-year-old son in 2004.