Although the proposal is far short of the full repeal sought by Gov. Martin O'Malley, the governor said it might be the best that death penalty opponents could hope for this year.
"I don't know of any state that has those specific restrictions, or anything like them," said Richard Dieter, director of the Death Penalty Information Center, a Washington-based not-for-profit that has been critical of capital punishment.
Baltimore County State's Attorney Scott D. Shellenberger, the top prosecutor in the county that uses capital punishment more than any other in the state, said the Senate's plan was preferable to repeal but would be too restrictive.
"We already have a narrow statute," he said, "and they are squeezing it even further."
Since Maryland reinstated capital punishment in 1978, five convicted murderers have been executed, and another five are on death row.
For the first time in three decades, the full Senate this week debated the death penalty, using a rare parliamentary procedure to resurrect a repeal bill killed last week in a committee. Lawmakers amended the bill during a chaotic evening session Tuesday that ended with proposals to restrict capital cases based on evidence.
Yesterday morning, Senate President Thomas V. Mike Miller and majority leader Edward J. Kasemeyer, both Democrats who support the death penalty, short-circuited another day of disorder by asking senators to accept the amended plan and move on.
Final Senate passage is expected this week, and then the plan moves to the House of Delegates, where it could be altered. Although Miller said he would not accept any legislation other than what his members approved yesterday, some delegates vowed to continue trying to abolish the death penalty.
"We want to pass a clean repeal," said Del. Samuel I. Rosenberg, a Baltimore Democrat. "It's important not to settle prematurely for less than what a majority of the House supports.
House Speaker Michael E. Busch, a Democrat, said yesterday that there probably are enough votes to pass a repeal in his chamber but acknowledged that straying too far from the Senate's version could sink that bill, which he said represents "a step forward."
He said the House might "enhance" the Senate bill by further restricting instances in which prosecutors could seek the death penalty.
House Judiciary Committee Chairman Joseph F. Vallario said "there's no guarantee" that his committee would approve the Senate version unchanged when it takes it up in about two weeks.
O'Malley, a Democrat, said he thought the Senate did its best to reach a consensus.
"It's not as good as repealing it, but it's progress," he said after an event in Baltimore last night.
Jane Henderson, director of Maryland Citizens Against State Executions, said death penalty opponents would spend the next few days working on a strategy. She said a full repeal is the only acceptable option but that looked unlikely this year.
Yesterday, lawmakers were still sorting out the turmoil and flurry of amendments that led to the gutting of the repeal plan, with several senators offering explanations of what happened.
Sen. Jennie Forehand, a repeal supporter, did not cast a vote on the first amendment to roll back a repeal, offered by Sen. James Brochin, a Baltimore County Democrat. She said she was in the amendment room and missed the vote.