Others say the reduction in executions is simply an effect of having fewer cases eligible for the death penalty.
“It’s because the murder rate is down,” said Kent Scheidegger, legal director at the California-based Criminal Justice Legal Foundation, which supports the death penalty.
“Also, prosecutors nationwide are being more selective in when they seek it — and that’s not necessarily a bad thing,” Mr. Scheidegger said, adding that supporters of capital punishment think the measure should be reserved for the worst crimes.
The number of death sentences issued across the nation increased from 77 last year to 80 this year, according to the Death Penalty Information Center.
Activists note that the number of death sentences remains far lower than the national peak of 315 sentences issued in 1996 and 1994.
Support for the death penalty also may have waned as politicians face difficult questions about exonerated inmates and the regulation of drugs used for lethal injections, Mr. Dieter said.
“It used to be a wedge issue. You could use it to isolate your opponent,” he said.
Capital punishment was absent from the Virginia governor’s race, in which Democrat Terry McAuliffe defeated Republican Attorney General Kenneth T. Cuccinelli II. Mr. McAuliffe has likened his views on the subject to those of former Gov. Mark R. Warner, who was not a death penalty proponent but insisted that he would enforce state law. Eleven executions were carried out during Mr. Warner’s term.
Maryland Gov. Martin O’Malley, a Democrat, made the death penalty a central issue of his agenda, winning a repeal of the law this year in his second term after two unsuccessful attempts during his first term.
“The fact that he made it an issue and took that chance and to see it succeed, for better or for worse, that will be an issue for him,” Mr. Dieter said of Mr. O’Malley, who is thought to be considering a run for president.
Seventeen other states have abolished capital punishment. Mr. Dieter said he expected one or two more states — perhaps Delaware, Colorado or New Hampshire — to attempt to abolish the death penalty next year.
The center also noted that finding a consistent means of carrying out executions has been an ongoing problem. Many drugs used in lethal injections are manufactured in Europe, where opposition to the death penalty has resulted in a ban on exporting drugs for executions.
California, North Carolina and Arkansas have not executed a prisoner in more than seven years in part because of their inability to settle on a lethal injection protocol, the center said in its report. Federal executions are on hold for the same reason.
Mr. Northup said it was unclear whether Virginia had experienced any issues obtaining drugs used in lethal injections. The last man executed in the state, Robert Gleason Jr., was put to death by electric chair.
Gleason was serving a life term for murder in May 2009 when he killed his cellmate and then another inmate a year later. He waived his appeals, insisting he deserved to die.