Kentucky lawmakers have been trying for years to outlaw the death penalty, to no avail.

But proponents of the latest bill, a bipartisan effort, have seized upon an argument that has been growing in popularity nationwide.

It’s just too expensive to execute people.

“We believe that strictly on the bases of costs, life without parole makes more sense,” Rep. David Floyd (R) told the Louisville Courier-Journal. Floyd, the House Republican whip, introduced a bill on Wednesday to repeal Kentucky’s death penalty.

At the very least, Floyd would like the state to figure out how much it’s spending on death penalty trials. Thursday, he estimated that these cases have cost the state $400 million since 1976. In that time, Kentucky has only executed three people, the last one in 2008.

“We’re talking about $130 million per execution to maintain a system that clogs the courts and delays finality for victims’ families,” he said.

There have always been moral arguments against the death penalty. Floyd said he opposes it because of his Christian faith. Furthermore, DNA evidence has produced a steady stream of death row exonerations in recent years, reminding the public that prosecutors and juries make mistakes.

“We have a system where the innocent are sacrificed so we can execute the b—–d,” Floyd said, noting that Kentucky has an alarmingly high error rate when it comes to capital convictions.

In 2011, the American Bar Association called for Kentucky to stop executing people until the state fixed its legal system. (Executions in Kentucky have effectively been on hold anyway since 2009, when the state’s Supreme Court ruled that its lethal injection procedures needed to be reviewed.) The ABA report reviewed death penalty cases since 1976 and found that 64 percent of defendants — 50 out of 78 — had seen their cases overturned on appeal.

Still, it’s been hard for Floyd to convince some of his fellow lawmakers to stand with him against executions. A 2013 Courier-Journal poll of registered Kentucky voters found that two-thirds want capital punishment.

Last year, he hit on his current point. He had been talking to the state’s public defender’s office, which spends millions handling death penalty cases. Floyd began to see the outlines of an argument that might appeal to his budget-minded friends in the GOP.

This idea that there’s something fiscally irresponsible about the death penalty is not new. But the talking point has become popular in recent years, as state governments continue to tread a shaky path out of the recession. In November, for instance, Kentucky faced a projected $135 million shortfall in its $9.8 billion budget going into 2015.

Several states have produced studies showing that when a prosecutor decides to go for the death penalty, the cost of the case balloons.

In a report released in January, professors at Seattle University found that, on average, death penalty cases cost 1.5 times as much, or about $1 million more, than similar murder cases not involving the death penalty. In particular, the government spends about three times more on defense costs for these trials. (The research was funded by the American Civil Liberties Union.)

In California, a study from 2011 estimated that the state spends $184 million a year on costs related to death penalty, totaling over $4 billion since the state brought back capital punishment in 1978.

These kinds of cases are expensive in part because defense lawyers are required to pull out all the stops when a person’s life is on the line.

“The ABA has put out guidelines that make it clear that people representing folks facing a death penalty have enormous responsibilities,” said Jordan Steiker, a law professor at the University of Texas. This adds to the cost of a trial — not just the lawyers’ fees, but fees for special experts, such as psychiatrists and litigation specialists. If a defendant can’t afford these measures (and most don’t), the bill goes to the state.

“Cost has really changed the practice on the ground,” Steiker said. The number of death penalty cases has plummeted in recent decades, he said, in part because prosecutors are becoming cautious of how expensive the trials are.

Steiker, who clerked for Supreme Court Justice Thurgood Marshall, published an article in 2010 explaining how these economic concerns have changed the debate surrounding the death penalty. “The high cost of administering the death penalty has become a prominent — perhaps the most prominent — issue in contemporary discussions about whether the penalty should be limited or abolished,” he wrote.

But will this argument gain ground in Kentucky? Floyd, the Republican representative, said he’s already changed a few minds. His bill hasn’t yet been penciled into the judiciary committee schedule, but he’s hopeful this will be the year that everything changes.