Execution evolution:

Stoning ... burning at the stake ... crucifying ... drawing and quartering ... chopping off a head with ax, sword or guillotine ... forcing someone to walk the plant ... hanging ... shooting ... electrocuting ... dropping potassium- cyanide pellets into containers of sulfuric acid, triggering fatal fumes ... injecting with a lethal drug cocktail ...

Detect the kinder and gentler death-penalty-method trend?

And now even lethal injection is branded as intolerably cruel - and increasingly unusual.

OK, so Clayton Lockett did struggle through a torturous 45-minute departure from this mortal realm a week ago today at the Oklahoma State Penitentiary in McAlester. One of his veins collapsed during the injection process, leaving him lingering - and writhing - in agony before he finally checked out with a heart attack.

Predictable laments about his last-act plight ensued.

Much closer to home, the South Carolina Radio Network's Matt Long reported Monday: "South Carolina is among those states that currently lack the [death penalty] drugs, according to the state Department of Corrections, which has not carried out an execution since 2011. That's the longest gap since no executions occurred from September 1991 to August 1995."

Corrections spokeswoman Stephanie Givens told the network: "We use pentobarbital, pancuronium bromide, and potassium chloride in the three-drug sequence. But we don't have any pancuronium bromide or potassium chloride .... and we probably won't be getting it."

That's because European Union drug manufacturers, long the major source of such deadly concoctions, have stopped feeding our capital-punishment habit.

And the Illinois-based drug and medical-device company Hospira, under pressure from death-penalty foes, got out of that grisly business in 2009.

South Carolina's death-row roster now stands at 45, none of whom has a date with death-penalty destiny yet. They never will if capital-punishment opponents have their way.

The United States was the only nation in the Americas to execute anybody last year.

China, however, executed thousands (that government doesn't release actual numbers) last year, and Iran's death-penalty tally was officially 369, unofficially around 700. You don't even have to kill anybody to be legally killed by those governments' "justice" systems. You also can't count on an easy way out, though China does frequently (but not always) use lethal injections.

No, being a member of that brutal club doesn't seem to reflect well on us.

But reflecting allegedly enlightened attitudes, America has softened on that hardest of hard lines, capital punishment, executing a mere 39 killers last year (16 of them in Texas alone).

Among the forces of change - and yes, logic - wearing down the dwindling ranks of us death-penalty diehards:

Capital punishment, as erratically practiced in the U.S., actually costs more than incarcerating a prisoner for life.

Not all convicted criminals are guilty.

Our nation and region carry an ugly history of racial disparities on which convicted murderers - and murder victims - pay that ultimate price. Plus, regardless of ethnicity, poor folks are far more likely to get the needle - or the chair - than rich folks.

Before putting the death penalty to death, though, review the ironclad case against Lockett:

He confessed, in irrefutable, evidence-confirmed detail, to kidnapping, beating and shooting (twice, with a shotgun) 19-year-old Stephanie Nieman in 1999, then telling an accomplice to bury her alive, which he did.

Lockett was convicted in 2000 of not just first-degree murder but rape, forcible sodomy, kidnapping, assault and battery, and burglary - and sentenced to death. Yet it took Oklahoma until last week, and then those additional, unplanned 45 minutes, to finally - and justifiably - carry out that punishment.

Back to our Palmetto State:

It's a long-term disgrace that Richard Valenti is still alive - and that the families of his victims (including the two girls, ages 13 and 14, he murdered in 1973 at Folly Beach) must annually endure the parole-hearing ordeal of making sure he stays locked up. At least his 18th parole bid was denied against last week.

Meanwhile, why in the modern world of pharmaceutical wonders can't we find - and maintain - a humane way to end the life of a first-degree murderer?

After all, even without "death panels," it's a well-known "secret" that medical professionals occasionally can - and do - mercifully put intensely suffering terminal patients out of their miseries with, well, lethal injections.

And it's no secret that the death penalty in the U.S. is on life support.

But before pulling the final plug on capital punishment in America, keep this in mind:

The killers we kill in South Carolina get to choose their manner of demise (lethal injection or electric chair).

The people they killed did not.

Frank Wooten is assistant editor of The Post and Courier. His email is wooten@postandcourier.com.