(Reuters) - Delaware's top court on Tuesday struck down the state's death penalty statute, arguing that it grants judges powers that juries should wield and that it is unconstitutional.

The 3-2 Delaware Supreme Court decision came in the case of Benjamin Rauf, who was charged with first-degree murder and robbery and being in possession of a firearm during the crimes. Prosecutors have been seeking the death penalty against Rauf.

The judges determined that since the state's death penalty law allows a judge to sentence a convict to death independent of a jury and also allows a jury to hand down a death sentence without a unanimous verdict, it violated the U.S. Constitution.

"Put simply, the Sixth Amendment right to a jury includes a right not to be executed unless a jury concludes unanimously that it has no reasonable doubt that is the appropriate sentence," the 92-page ruling said.

"Throughout our history, capital sentencing has been a 'responsibility traditionally left to juries,' and the decision of whether a 'fellow citizen should live or die' has been considered a responsibility too great for any one person to make alone," the ruling said.

Delaware Governor Jack Markell, a Democrat, applauded the ruling.

"The use of capital punishment is an instrument of imperfect justice that doesn't make us any safer," Markell said in a statement. "It is my hope that today's decision will mean that we never see another death sentence in our state."

Delaware Department of Justice spokeswoman Nicole Byers said the office was reviewing the decision.

Rauf's attorney, Santino Ceccotti, said he was "elated" with the ruling.

"We're still going through the decision, it's a lengthy one, but we're very happy with the court's decision," he said.

Ceccotti added that the ruling would require all capital offense cases currently pending statewide to be prosecuted again with non-capital charges, though it was not immediately clear if the court's ruling would be retroactive.

The decision said it would fall to the state's General Assembly to decide whether to craft a new death penalty statute that does not violate the U.S. Constitution.

The ruling noted that the U.S. Supreme Court made a similar determination when it struck down Florida's death penalty statute in January, arguing that a jury, not a judge, was required to impose a death sentence.

(Reporting by Curtis Skinner in San Francisco; Editing by David Gregorio, Toni Reinhold)