By Ian Simpson
WASHINGTON (Reuters) - Maryland became the 18th U.S. state to abolish the death penalty on Thursday when Governor Martin O'Malley signed a bill outlawing capital punishment in the state.
O'Malley, a Democrat mentioned as a potential presidential candidate in 2016, had pledged to sign the bill, which the Democrat-controlled legislature passed in March. The law replaces capital punishment with a sentence of life without parole.
"With the legislation signed today, Maryland has effectively eliminated a policy that is proven not to work," O'Malley's office said in a statement.
The governor's office said the death penalty does not deter crime, cannot be administered without racial bias and costs three times as much as life without parole. A mistake cannot be reversed if an innocent person is put to death, the statement added.
Five other states - Connecticut, Illinois, New Mexico, New York and New Jersey - have repealed capital punishment since 2007, according to the Death Penalty Information Center.
"That's six states in six years," said Richard Dieter, the Center's executive director.
Since Maryland reinstated the death penalty in 1978, 58 people have been sentenced to death in the state, but only five sentences have been carried out. Maryland has five men on death row, and its last execution took place in 2005.
EXECUTIONS IN DECLINE
The number of U.S. executions has fallen from a peak of 98 in 1999 to 43 each in 2011 and 2012, according to the Death Penalty Information Center. The pace has slowed even more in 2013, with 10 so far this year.
Texas has by far the highest number of executions since the U.S. Supreme Court restored the death penalty in 1976, at 496, according to the center. It is trailed by Virginia at 110.
Dieter said the death penalty had fallen out of favor largely because lawmakers and the public more and more feared that innocent people could be executed. He noted that lengthy legal appeals made it an expensive proposition.
"It all adds up (as) a costly and rarely used punishment," he said.
Kent Scheidegger, a death penalty advocate and legal director of the Criminal Justice Legal Foundation in Sacramento, California, said some crimes, such as last month's bombings at the Boston Marathon, justified the punishment.
"The main reason is just simple justice," said Scheidegger. "There are some crimes where a lesser penalty is insufficient."
He added that capital punishment could act as a deterrent to crime when correctly applied.
Multiple states had bills pending to abolish the death penalty but it was unclear which might be the next to overturn it, Dieter said. Among possible contenders is Nebraska, where the single-chamber legislature turned down a repeal bill in March by one vote.
The Florida Senate this week moved to speed up executions by sending to Governor Rick Scott reforms designed to keep condemned inmates from spending decades on death row.
O'Malley, a former Baltimore mayor and prosecutor, succeeded in his second attempt since 2009 to overturn capital punishment. It is part of a series of socially liberal measures he has championed in Maryland, including gun control, same-sex marriage and letting undocumented immigrants pay in-state tuition at state colleges.
Ted Sheckels, a political analyst at Virginia's Randolph-Macon College, said O'Malley's progressive stance, including the death penalty repeal, could help him if he decides to run for president in 2016.
"There have been a number of things that position him on the liberal side of things, which in a Democratic primary is where you want to be," he said.
(Reporting by Ian Simpson; Editing by Barbara Goldberg, Scott Malone, Lisa Von Ahn and Dan Grebler)