California voters on Tuesday rejected a ballot measure that would have repealed the state's death penalty.

Proposition 34 lost by about 6 percentage points, dimming the hopes of death penalty opponents who were trying to abolish the death penalty in California and clear the largest death row in the nation.

Proposition 34 marked the first opportunity in more than three decades for California voters to decide whether to retain the death penalty, which has been scrapped by a number of other states in recent years.

"The people of California sent a clear message that the death penalty should still be implemented for those who commit the most heinous and unthinkable crimes," McGregor Scott, former United States Attorney and Co-Chair for No on Prop 34, said in a statement.

Scott added: "Now that the people have re-affirmed their support for the death penalty, we are committed to coming back to the voters with a reform proposition to streamline and expedite the death penalty in California, The problems with delay and expense of California's death penalty are entirely fixable."

Natasha Minsker, manager of the Proposition 34 campaign, indicated the vote would not be the last political effort to abolish the death penalty.

"This issue is not going away," she said Wednesday. "53 percent is not a mandate for carrying out executions. This state is clearly evenly divided on the death penalty."

The measure would have replaced the death penalty with life in prison without the possibility of parole and converted the death sentences of California's 727 death row inmates to life. It would have reverberated through the national debate over the death penalty, while immediately removing nearly a quarter of the more than 3,100 death row inmates now awaiting execution across the country.

Backers of the measure focused their arguments on the cost of California's notoriously slow capital punishment system, saying it would save hundreds of millions of dollars a year at a time when the state is facing a budget crunch.

The Proposition 34 campaign enlisted a roster of the rich and famous to bankroll the effort, gathering more than $7 million to far outspend the opposition.

But law enforcement officials, victims' rights groups and three of California's former governors aligned against the measure, arguing that the death penalty should be preserved for the state's most heinous killers. They refuted the potential cost savings, saying the estimates were inflated and that the ponderous death penalty system should be repaired, not replaced.

California has executed just 13 inmates since restoring the death penalty in 1978, the result of an appeals process that takes decades and often results in death sentences being overturned long after a murderer is sent to San Quentin. Just last month, a federal appeals court overturned the 1978 death sentence of condemned killer Douglas Stankewitz, the state's longest serving death row inmate.

Executions have been on hold for nearly seven years in California, the result of ongoing legal challenges to the state's lethal injection method. Those court battles will continue to unfold, likely ensuring another year or more of delays before the state can realistically resume executions.

However, while the legal battles have unfolded, at least 13 death row inmates have exhausted all of their legal appeals, raising the prospect that California will experience an unprecedented spate of executions if Proposition 34 is rejected and further legal roadblocks are removed.

Californians have historically demonstrated strong public support for the death penalty, adopting the 1978 law with more than 70 percent of the vote. But support has been eroding in recent years, prompting death penalty foes to make a move to abolish a system that both current Chief Justice Tani Cantil-Sakauye and former Chief Justice Ronald George have called "dysfunctional."

Gov. Jerry Brown and Attorney General Kamala Harris took no public position on Proposition 34, but Brown revealed that he voted for the measure after filling in his ballot in Oakland on Tuesday. Unlike other states where legislators have repealed the death penalty, only California voters can abolish the death penalty here because it's in the state constitution.