A repeal of Maryland's death penalty is expected to pass the state Senate next week, but voters could have the ultimate say on its fate in the 2014 election.

Senate President Thomas V. Mike Miller Jr., D-Prince George's and Calvert counties, has said he expects the issue, which received preliminary approval Friday, to go to voter referendum. That possibility was improved when senators eliminated a funding provision, as legislation that can be considered a budget item cannot go to referendum under Maryland rules.

Police and prosecutors throughout the state are fighting to keep the death penalty for those who commit heinous crimes. They argue that capital punishment is a valuable tool and that the death penalty is the only thing deterring violent criminals already serving prison terms from killing corrections officers or one another.

On the other side is a coalition of religious groups, human rights advocates and the National Association for the Advancement of Colored People. They say the death penalty does not deter violent crime and the state should eliminate any possibility of putting to death an innocent person.

The repeal bill -- one of Democratic Gov. Martin O'Malley's legislative priorities this year -- passed a key test vote Friday when senators rejected an amendment 27-19 that would have kept the death penalty for the most heinous murders.

Despite the major push to end capital punishment, Maryland hasn't executed anybody since 2005, and O'Malley's administration has refused to implement procedures to allow the execution of the state's five current death row inmates to go forward.

A Gonzales Research poll from January shows 49 percent of Marylanders support the death penalty, while 44 percent oppose it. The margin of error was plus or minus 3.5 percent.

That doesn't worry proponents of repeal.

"There's no organized opposition," said Jane Henderson, executive director of the coalition Maryland Citizens Against State Executions. "All of the intensity on the issue is on our side."

Religious groups frame the repeal as a sanctity of life issue in line with the tenets of their faith. Groups like Color of Change and the NAACP argue the death penalty is disproportionately used against blacks.

Harford County State's Attorney Joseph Cassily calls that "bogus," saying 80 percent of the murders committed in Maryland are by black men.

Cassily said if the death penalty is repealed, people already serving life sentences could murder with impunity.

"This is not repealing the death penalty, this is about legalizing certain forms of first-degree murder by removing the penalty," he said.

That sentiment is shared by a number of groups representing law enforcement, such as the Maryland State Lodge Fraternal Order of Police, Maryland Troopers Association and the Maryland Sheriffs' Association.

Those groups argue a criminal is less likely to kill an officer during the commission of a crime out of fear of the death penalty.

"Law enforcement officers are the last line of defense between anarchy, chaos and all that is good in our society," wrote state FOP Legislative Chairman Percel O. Alston Jr. in testimony before the House Judiciary Committee.