Death by firing squad: In the popular imagination, it brings up images of insurgencies, or military treatment of deserters and captured spies.

The question for US states facing profound problems with the lethal injection protocol mostly used today is whether to bring back the firing squad as an execution option, especially in light of the botched Oklahoma execution-by-injection of Clayton Lockett in April.

Utah is the latest of several states where lawmakers have proposed replacing lethal injection with more anachronistic execution solutions including firing squads, so far unsuccessfully. The last execution by firing squad took place in Utah in 2010, where five state police sharpshooters simultaneously aimed and fired at convicted killer Ronnie Lee Gardner, killing him with shots to the heart.

It was the third death by firing squad in the US since the Supreme Court overturned a death penalty ban in 1976. (Despite all US states now banning firing squads, some inmates in Utah and Oklahoma can still choose firing squad, given grandfather provisions in the law, which is how the Gardner execution happened.)

“If adopted, [states seeking such] measures could mark a return to the days of inmates being hanged, electrocuted, or shot by marksmen,” the Associated Press surmised in January.

The ethical exploration of society’s ultimate sanction has been going on for decades.

But it’s been complicated more recently with European pharmaceutical companies refusing to sell key lethal injection drugs to US death penalty states, on ethical concerns about capital punishment. Most other countries that still have the death penalty either hang or shoot their condemned, with only six countries, including the US, relying on lethal injections. (Three countries still behead.) One hundred forty countries ban the death penalty.

But to some elected state officials, drug shortages and legal challenges have sparked a renewed focus on what is a humane execution.

It was only a generation ago when legislatures began, for a variety of reasons, to ban what many thought were barbaric options in order to make capital punishment more palatable and avoid judicial concerns about sanctions that violate the US Constitution’s guarantee against cruel and unusual punishment.

To be sure, a majority of Americans still back the death penalty, but polls say a growing number want states to look at alternatives after the botched Oklahoma execution. Literally a guinea pig for a new lethal injection “cocktail,” Mr. Lockett woke up and spoke during the procedure, getting so agitated that attending physicians had to close a curtain so that witnesses couldn’t see how he ultimately died nearly an hour after the first injection.

In a recent NBC News poll, Americans showed openness to exploring options other than lethal injection in order to keep the death penalty in place. One in 3 said the death penalty should be abolished if states can’t perform humane lethal injections.

But 20 percent of respondents said they’d like see the gas chamber reinstated, 18 percent would like to bring back the electric chair, 12 percent want firing squads, and 8 percent would prefer to see hanging used for the ultimate sanction.

“Lethal injection is someone’s very gross interpretation of killing someone humanely,” Kuni Beasley of Frisco, Texas, told pollsters, suggesting instead a return to hanging.

Utah state Rep. Paul Ray (R) said he’ll introduce his firing squad proposal next year. Unlike similar bills that faltered in Wyoming and Missouri earlier this year, the Utah bill might fly, historians say, in part because of Mormon tradition, which is heavily influential in Utah.

“Some early Mormon leaders believed in blood atonement for the most egregious sins,” NPR reported at the time of Ronnie Lee Gardner’s execution by firing squad in 2010. “The Church of Jesus Christ of Latter-day Saints has since renounced any connection to blood atonement. And the belief has all but disappeared among Utahns today.”

But even given regional variations in how people view capital punishment, the current push toward methods many thought society had left behind is for some observers a troubling development.

“It’s difficult to understand the issue of how can we still be engaged in this form of barbarism,” Elisabeth Semel, director of the Death Penalty Clinic at the University of California, Berkeley School of Law, told Discovery News earlier this year.