ST. LOUIS (AP) — The U.S. Supreme Court on Tuesday denied a stay of execution for Missouri inmate Michael Worthington, who is scheduled for lethal injection for the rape and killing of a neighbor in 1995.

His execution planned for just after midnight Wednesday is set to be the nation's first since one in Arizona last month in which an inmate gasped more than 600 times while taking nearly two hours to die.

The 43-year-old Worthington had been sentenced to death for the September 1995 attack on 24-year-old Melinda "Mindy" Griffin during a burglary at her home.

Worthington's lawyers had filed last-minute appeals Tuesday to the Supreme Court and asked for clemency, which was denied by Gov. Jay Nixon on Tuesday night.

"I figure I'll wake up in a better place tomorrow," Worthington said earlier Tuesday. "I'm just accepting of whatever's going to happen because I have no choice. The courts don't seem to care about what's right or wrong anymore."

His lawyers had called into question the Arizona execution and two others that were botched in Ohio and Oklahoma, as well as the secrecy involving the drugs used during the process in Missouri.

Democratic Gov. Jay Nixon was weighing Worthington's clemency request, spokesman Scott Holste said.

The three botched executions in recent months have renewed the country's debate over lethal injection. In January, an Ohio inmate snorted and gasped for 26 minutes before dying. A few months later in Oklahoma, an inmate died of an apparent heart attack 43 minutes after his execution began. Most lethal injections take effect in a fraction of that time, often within 10 or 15 minutes.

Ohio, Oklahoma and Arizona all use midazolam, a drug more commonly given to help patients relax before surgery. In executions, it is part of a two- or three-drug lethal injection.

Texas and Missouri instead administer a single large dose of pentobarbital — often used to treat convulsions and seizures and to euthanize animals. Missouri changed to pentobarbital late last year and since has carried out eight executions during which inmates showed no obvious signs of distress.

Missouri and Texas, like most states, refuse to name their drug suppliers, creating a shroud of secrecy that has prompted lawsuits.

On Tuesday, Griffin's 76-year-old parents anticipated witnessing Worthington die.

"It's been 19 years, and I feel like there's going to be a finality," Griffin's mother, Carol Angelbeck, told The Associated Press by telephone Tuesday.