New Jersey prosecutors no longer have to prove a defendant is mentally fit to be executed, the state Supreme Court ruled Tuesday.

The decision shifts the burden of proving mental retardation to defendants trying to avoid death penalty, putting New Jersey in line with most other states.

The ruling likely won't affect any of the state's nine death row inmates anytime soon. New Jersey reinstated the death penalty in 1982 but has a moratorium on executions while a legislative panel evaluates capital cases. Its last execution was in 1963.

Tuesday's decision stemmed from the case of Porfirio Jimenez, a Honduran day laborer in prison on charges he sexually assaulted a 10-year-old boy before murdering him in 2001. Jimenez's lawyers claimed he was mentally retarded, with an IQ of 68.

A 2002 U.S. Supreme Court ruling declared executing mentally retarded criminals to be a violation of the Constitution's ban on cruel and unusual punishment, but it left it to states to decide whether the burden of proof about a defendant's mental status lies with the prosecution or defense.

In its ruling Tuesday, the New Jersey high court's majority likened a claim of mental retardation to a claim of insanity, which is considered an "affirmative defense" and has to be proved by the defendant.

Justices Barry T. Albin and Virginia Long dissented, arguing that placing the burden of proof on the defendant to show mental retardation would increase the chance of wrongly executing a mentally retarded person.

Every other state that has addressed the issue has determined a defendant should bear the burden of proof to prove mental retardation. Twelve states do not have death penalties.

Susan Remis Silver, one of Jimenez's public defenders, said the decision was disappointing.

"Our client's life hangs in the balance and this decision widens the margin of error that a mentally retarded defendant will be executed in New Jersey," she said.