OKLAHOMA CITY — The night that Clayton Lockett died, a small group of protesters with the Oklahoma Coalition to Abolish the Death Penalty held a quiet vigil outside the gates of the Governor’s Mansion.

It’s tradition for the group, which has less than a dozen active members and whose annual dinner draws a few hundred. For each execution at Oklahoma State Penitentiary in McAlester, no more than 15 people usually gather at the governor’s residence 120 miles away in Oklahoma City.

At 6 p.m., when an execution begins, they fall silent to ponder and mourn another life lost to the death penalty. They don’t say a word until a mansion security guard comes to tell them that the inmate has died — usually a few minutes later.

It didn’t happen that way last April 29.

“It began to be distressing to some of our members when 10, 20 minutes went by, and we hadn’t heard anything,” said the Rev. Adam Leathers, a spokesman for the group, of Lockett’s execution. The moment of silence stretched on for 43 minutes.

The group later learned that Lockett’s execution hadn’t gone as planned. A fatal drug cocktail missed his vein, due to a misplaced IV, leaving him writhing on the gurney.

The botched procedure, which became a global story, led the state to suspend executions, revisit its death-penalty protocols and renovate the death chamber in McAlester.

But it’s done little to change the minds of many Oklahomans about capital punishment. If anti-death penalty groups hoped that Lockett’s death would widen opposition, they’ve found little evidence that public opinion has shifted.

Days after Lockett’s belabored execution, Gallup conducted a national poll asking Americans specifically about the execution, noting that Lockett “appeared to suffer for an extended period of time until finally dying of a heart attack.”

“The case did not fundamentally alter Americans’ perceptions of the death penalty, however, with a solid majority viewing it as morally acceptable,” Gallup wrote of its poll’s findings. The poll found that 61 percent of Americans found the death penalty “morally acceptable,” only a percent less than in 2013.

The study didn’t isolate Oklahomans’ opinions, and it doesn’t appear that anyone has conducted polling on the issue in the state since then.

But those who study public opinion say there’s likely been little change.

“It is not surprising that this one event, while significant, seems not to have caused an overwhelming shift in public opinion on the death penalty in Oklahoma,” said Eric French, an assistant political science professor at Oklahoma State University, who specializes in public opinion.

“People’s longstanding opinions are very resistant to change for all kinds of reasons. One reason is that people with differing political viewpoints often do not perceive events like this in the same way,” French said in an email.

Oklahoma, with its staunch convictions, would be inhospitable to most any anti-death penalty campaign, he noted. “Conservatives tend to favor the death penalty, and people’s opinions on issues like this are often deeply-rooted,” he said.

Leathers notes that leaders of the National Coalition to Abolish the Death Penalty haven’t given the Oklahoma chapter any money to expand recruiting — nor has his group asked.

But, with better funding, he believes the group could make a difference by disseminating the facts about the death penalty.

“Regrettably, yes, it’s still popular here, but I don’t think it would be so popular if all the facts were laid out,” he said.

And Leathers said he’s concerned about what’s to come Thursday, when Charles Warner is strapped to the gurney in McAlester’s death chamber for the first execution since Lockett’s botched procedure.

A parade of men are scheduled to follow in executions planned through the end of March.

“We frankly are terrified about what it going to happen on Thursday,” he said. “We fear that another human being is going to be tortured to death. We as citizens, we talk tough and say he deserves it, but we’ll be sitting comfortably on our couch that evening.”

Richard Dieter, executive director of the Death Penalty Information Center, which advocates for an end to capital punishment, contends that while sentiment remains strong for executions in Oklahoma, jurors and prosecutors in the state actually have reduced the number of death sentences since the ’90s.

The era of multiple executions a year is nearing an end, he said. Only one Oklahoma inmate was sentenced to death in 2012 and in 2013, he notes, and there were no death sentences handed down the previous two years.

“They’re not going to have multiple executions in the future given the number of death sentences in the figure,” he said. “Something is changing. It’s partially concern about mistakes, fairness, moral or religious concerns.”

He said inmates are also taking more plea bargains and life-without-parole sentences.

“For the people, it’s not as relevant as it used to be,” he said of executions.

The state has executed 111 people since it reinstated capital punishment in 1990. Another 50 inmates — including Warner — are now serving on death row.

On Thursday night, Leathers said his group will be back in front of the Governor’s Mansion, peacefully protesting starting at 5:15.

The vigil is open to the public.