Death penalty laws are on the books in 31 states, but only five carried out executions last year. Now Arkansas is rushing to execute death row inmates at an unprecedented pace this month, before the state's supply of lethal drugs expires.

Nationwide the number of executions are down, as states struggle to obtain execution drugs that pass constitutional muster. Pharmacies are refusing to provide the deadly combinations of paralytics and fast-acting sedatives needed to put prisoners to death.

"I'll admit, it's more and more difficult to carry out the sentence of the death penalty," says Republican Andy Gipson, chairman of the Mississippi House Judiciary B Committee. Mississippi hasn't executed anyone since 2012, but Gibson says that for the past six years lawmakers have had to tweak the state's death penalty statute to keep it constitutional.

"It's been a huge problem," he says. "We try to see if we can come up with another suitable formula of injection that will be humane, and then another lawsuit gets filed to say we can't do that either."

This year Mississippi came up with a back-up plan: Should its lethal injection protocol not stand, it will turn to a hierarchy of old-school execution methods — the gas chamber, the electric chair or a firing squad.

"It is the law of the land — and until it's changed, until it's altered, you have to have a way to carry it out," Gipson says.

Utah also allows for the firing squad, and Alabama, Florida and Tennessee have brought back the electric chair.

States are coming up with these alternatives to deal with what the Death Penalty Information Center deems a de facto moratorium on executions. The group opposes capital punishment and has documented a drop in executions nationwide.

"There's been a precipitous decline in the number of both executions and death sentences in the last five years," says executive director Robert Dunham, adding that two-thirds of the states either don't have the death penalty or haven't executed anyone in more than a decade.

"Executions have been concentrated in a small number of southern states," says Dunham. "The rest of the country is largely not carrying out executions. If they do, they're doing so rarely."

A total of 20 people were put to death last year — the fewest since 1991 — all in Georgia, Texas, Alabama, Florida and Missouri.

Seven states have abolished the death penalty in the past 15 years, but public support remains. For instance, after the Nebraska legislature repealed capital punishment in 2015, voters reinstated it through a referendum last year.

Dunham says courts have allowed for more convictions to be reviewed, and the result has been fewer death sentences carried out.

"The single most likely outcome of a capital case once somebody is sentenced to death is not that they will be executed — it's that their conviction or death sentence will be overturned," he says.

That fact has led some officials to rethink capital punishment. Newly elected prosecutors in Denver and Orlando, Fla., have said they won't seek death sentences.

That decision sparked controversy in Florida, where Republican Gov. Rick Scott has removed State Attorney Aramis Ayala from handling 22 murder cases because of her refusal to seek the death penalty.

"It is a response to a broken system," says Ayala, first black prosecutor elected in Florida.

When she took office, Ayala says, Florida's death penalty law was unconstitutional, and existing sentences were under judicial review.

"I'm looking at cases from 1970," she says. "I'm looking at cases that existed when I was 2 years old, and families have been waiting on death sentences since then. And I had to look at an open case in my office and say, 'am I going to throw this case into that pile of chaos?' "

Now she faces a backlash as lawmakers are calling for her to be removed from office and threatening to cut her budget. Ayala is fighting back, and says she plans to sue the governor for taking away her caseload.

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