While the death penalty never emerged as a major issue during the 2016 campaign, Election Day saw key victories for supporters of capital punishment, which has seen its popularity and use decline nationwide.

Voters in three states - Nebraska, California and Oklahoma - showed their support for the practice, rejecting measures that would abolish it and, in one case, giving lawmakers more room to find new execution methods.

In Nebraska, voters opted to repeal a bill that was set to abolish the death penalty last year. A referendum Tuesday saw 60 percent of voters opting to scrap that bill, restoring the death penalty there.

This bill was the source of a back-and-forth between the Nebraska lawmakers who passed the legislation in May 2015 and Gov. Pete Ricketts (R), who called it "cruel" to the victims of people sentenced to death and vowed to veto it.

After lawmakers in Nebraska voted to abolish capital punishment there, Ricketts vetoed it, prompting the legislature to take another vote and override him. Cherry-red Nebraska then became the 19th state in the country to ban the death penalty, but opponents quickly said they would push to get the bill onto the 2016 ballot. During that campaign, Ricketts gave a reported $300,000 to a group fighting to keep the death penalty in the state.

The state had some highly-publicized problems obtaining lethal injection drugs, and last December, Ricketts said that he would not make any further efforts to get said drugs until voters decided on the measure. He also said the state would not seek to execute any of its 10 death row inmates; Nebraska has not carried out an execution since 1997.

Ricketts said in a statement after the death penalty bill was repealed that his office would work with Doug Peterson, the state's attorney general, to "make capital punishment work again in Nebraska to protect public safety."

"The death penalty may very well be gone nationwide before Nebraska ever carries out another execution," Shari Silberstein, executive director of Equal Justice USA, an anti-death penalty group, said in a statement. "This vote sentences Nebraska taxpayers to spend millions more wasted dollars, as the death penalty continues towards it's inevitable demise."

The outcome in Nevada came as executions and death sentences nationwide have continued to decline, and fewer states carry out executions each year.

"The long-term trend is still pretty clear," Robert Dunham, executive director of the Death Penalty Information Center, said in an interview Wednesday. "The long-term trend has been away from the death penalty."

Voters in California opted to reject a proposal that would have abolished the death penalty, voting against it by a margin of 53.9 percent to 46.1 percent.

Meanwhile, California voters also decided by a very narrow margin to pass a measure that would effectively speed up the pace of executions. This proposal won with 50.9 percent of the vote, winning passage with a little more than 151,000 votes out of more than 8.2 million cast.

The measure that passed would mandate earlier appointment of appellate attorneys for death-row inmates and set earlier deadlines for when appeals must be filed and decided.

California has not carried out an execution since 2006, owing to issues with its lethal injection protocol, but it is home to the country's largest death row. One in four death-row inmates nationwide are in California, but death sentences dramatically outpace actual executions. Since 1976, the state has executed 13 inmates.

The contrasting votes in California fold into what Dunham described as a shifting climate around capital punishment that is unfolding in fits and starts. He said that California's votes "are always surprises because no one is reliably able to predict what California voters are going to do," while adding that the vote in Nevada also reflected a political fight among lawmakers over the death penalty, rather than just capital punishment itself.

Nationwide, Durham said that in other down-ballot elections - including, for example, Kansas Supreme Court justices targeted for overturning death penalty cases - the death penalty did not appear to be an issue that swayed voters to oust people in office.

"The death penalty appears to have lost its traction as a wedge issue," he said.

Oklahoma voters opted by a 2-to-1 margin to pass a proposal adding language to the state constitution declaring that the death penalty is not cruel and unusual punishment.

That measure also gives lawmakers in Oklahoma - which, last year, became the first nationwide to make nitrogen gas one of its backup methods of execution - the ability to adopt "any method of execution not prohibited by the United States Constitution."

This proposal was passed while states are struggling to obtain drugs for lethal injections, the primary methods of execution in the country, and gives lawmakers there some wiggle room down the line should they decide they need another option.