Texas scheduled to execute 500th prisoner, Kimberly McCarthy

(AP) HUNTSVILLE, Texas - Texas is approaching a grim milestone: It will soon execute the 500th prisoner since the death penalty resumed in the United States.

On Wednesday, barring a reprieve, Kimberly McCarthy will be put to death via lethal injection.

PICTURES: 10 Noteworthy Texas Executions

The number far outpaces the execution total in any other state. But it also reflects the reality of capital punishment in the United States today: While some states have halted the practice in recent years because of concern about wrongful convictions, executions continue at a steady pace in many others.

The death penalty is on the books in 32 states. On average, Texas executes an inmate about every three weeks.

Still, even as McCarthy prepares to die, it's clear that Texas, too, has been affected by the debate over capital punishment. In recent years, state lawmakers have provided more sentencing options for juries, and courts have narrowed the cases in which the death penalty can be applied. In guaranteeing DNA testing for inmates and providing for sentences of life without parole, Texas could well be on a slower track to execute its next 500 inmates.

"It's a very fragile system" as attitudes change, said Mark White, who presided over 19 executions as governor from 1983 to 1987.

"There's a big difference between fair and harsh. ... I think you have (Texas) getting a reputation for being bloodthirsty, and that's not good."

Texas has accounted for nearly 40 percent of the more than 1,300 executions carried out since murderer Gary Gilmore went before a Utah firing squad in 1977 and became the first U.S. inmate executed following the Supreme Court's clarification of death penalty laws. (Texas had more than 300 executions before the pause.) Virginia is a distant second, nearly 400 executions behind. Texas' standing stems both from its size, with the nation's second largest population, and its tradition of tough justice for killers.

Still awaiting punishment in Texas are 282 convicted murderers.

Some may be spared. Supreme Court rulings have now excluded mentally impaired people or those who were under 18 at the time of their crime. Legal battles continue over the lethal drugs used in the process, mental competence of inmates, professional competence of defense lawyers and sufficiency of evidence in light of DNA forensics technology.

Texas Gov. Rick Perry, who has presided over more than half of the state's executions, said that the recent changes have helped make Texas' system fairer. In addition to the new sentencing options, he signed bills to allow post-conviction DNA testing for inmates and establish minimum qualifications for court-appointed defense attorneys.

"I think our process works just fine," Perry said last year during his unsuccessful presidential campaign. "You may not agree with them, but we believe in our form of justice. ... We think it is clearly appropriate."

So do most Texans.

A 2012 poll from the Texas Tribune and the University of Texas showed only 21 percent opposed to capital punishment.

Still, re-examinations of convictions have raised questions about whether some of those executed may have been innocent. The suspect cases included the 2004 execution of Cameron Todd Willingham for the arson deaths of his three young children. Arson experts consulted by a state panel determined evidence used to gain the conviction did not meet scientific standards. But Texas Attorney General Greg Abbott later barred the panel from further review of the trial evidence.

Over the years, the Texas execution list has provided a portrait of violent crime in a state where many people are armed, both good and bad, and juries have little tolerance for murderers.

Those executed have ranged from relatively common cases -- robbers who killed store clerks, drug users who killed other drug users, spouses killing each other -- to the bizarre and sensational. Ronald Clark O'Bryan, nicknamed the "Candy Man," poisoned his son's Halloween candy to collect on an insurance policy. Angel Resendez, a serial killer, rode the rails, stopping along the way to murder strangers. Lawrence Russell Brewer dragged a black man behind a pickup truck in a racist killing.

In the prison town of Huntsville, executions have become a well-worn ritual.

For more than 20 years, Dennis Longmire has been a fixture outside the fortress-like prison on execution evenings, holding a lit candle on a street corner. Hundreds of demonstrators once gathered there but interest has long since subsided.

"Texas continues to march to a different beat," as other states drop the death penalty, says Longmire, a criminal justice professor at nearby Sam Houston State University. He calls the execution total "staggering."

Kimberly McCarthy, convicted of killing a 71-year-old neighbor during a robbery in 1997, is among eight inmates scheduled for execution over the next four months. She would be the first female put to death in the U.S. in three years and the 13th woman since the Supreme Court allowed capital punishment to resume.

McCarthy, 52, was condemned for using a butcher knife and candelabra to beat and fatally stab retired college professor Dorothy Booth at the victim's Lancaster home. Evidence showed the former nursing home therapist used the knife to sever Booth's finger to steal her wedding ring.

McCarthy, who is linked to two other slayings, already has had her execution date pushed back twice this year. Her attorney, Maurie Levin, is trying to halt her execution again, contending black jurors improperly were excluded from her trial by Dallas County prosecutors.

Levin said there has been a "pervasive influence of race in administration of the death penalty and the inadequacy of counsel -- a longstanding issue here."

Even remarkable incidents in the death ritual can become mundane in the steady procession.

In 2000, Ponchai Wilkerson stunned officials when he spit out a small handcuff key he had kept hidden in his mouth as he prepared to die.

"In another state you live with that for a long time," said Jim Willett, who became warden at the Huntsville Unit in 1998 and oversaw 89 executions. "Here in Texas, another one is coming a few days later and you've forgotten that one before."

Complete coverage of Kimberly McCarthy on Crimesider