Maryland Gov. Martin O'Malley speaks at a rally in support of repealing the state's death penalty in Annapolis on Jan. 15. O’Malley’s repeal bill will go to the Senate floor after being approved by a committee on Thursday night. (Patrick Semansky/AP)

Gov. Martin O’Malley’s bill to abolish Maryland’s death penalty cleared a tall hurdle Thursday evening as a key Senate committee approved the measure for the first time and sent it to the full chamber for a vote next week.

The same Senate panel, which voted 6 to 5 for the repeal bill, later signed off on sweeping gun-control legislation, another top O’Malley priority, in a voting session that stretched until nearly midnight.

After making several changes, the panel voted 7 to 4 in favor of the bill, which would ban assault weapons, preclude more mental health patients from purchasing firearms, tighten school security and impose some of the strictest gun-licensing requirements in the country.

Both are marquee measures for O’Malley (D) in the 90-day session, which reaches its midpoint Friday. The House of Delegates is poised to weigh both bills in coming weeks.

The approval of the repeal bill followed spirited debate from members of the Judicial Proceedings Committee on both sides of the issue.

“Human beings make mistakes,” said Sen. Brian E. Frosh (D-Montgomery), the panel’s chairman, who argued that Maryland risked executing an innocent inmate by keeping capital punishment on the books. “No matter how hard we try . . . to find a way to beat all the error out of our system, I don’t believe that’s possible.”

Opponents of the repeal countered that lawmakers were robbing prosecutors of an important tool.

“We really are reducing our ability to deal with the most severe crimes committed in our state,” said Sen. Joseph M. Getty (R-Carroll), who voted against the repeal. “In many cases, these are crimes against humanity that need a sufficient sanction.”

All six members of the panel who voted for the bill are Democrats. Two other Democrats joined three Republicans in opposing the repeal.

The Judicial Proceedings Committee has long been seen as the biggest stumbling block for repeal legislation.

Maryland, where five prisoners sit on death row, would become the 18th state to outlaw capital punishment. Death sentences would be replaced with life in prison without the possibility of parole.

Ultimately, the issue could be decided by voters. If a repeal passes, opponents have vowed to take advantage of a process in Maryland that allows citizens to petition just-passed laws to the ballot.

Sen. Robert A. Zirkin (D-Baltimore County) was considered the swing vote on the Senate committee.

During the debate Thursday, Zirkin said he had managed to separate his emotional response about people who commit murders from his legal analysis of the issue.

“As heinous and awful as these individuals are, I just think the state should not be involved in these executions,” Zirkin said.

Although the death penalty remains on the books in Maryland, the state has not executed a prisoner since 2005. The state’s highest court ruled in 2006 that new regulations on lethal injection would have to be adopted for capital punishment to continue. Under O’Malley, that has not happened.

With Zirkin’s support, there are 26 senators who are either co-sponsoring the repeal bill or who have said in interviews that they plan to support it. That’s two more than are required to pass bills on the Senate floor.

Advocates of repealing the death penalty have long regarded the House as the more friendly chamber to their cause.

O’Malley last sponsored a repeal bill in 2009 and was unable to win a majority vote from the Judicial Proceedings Committee.

As a courtesy to the governor, Senate President Thomas V. Mike Miller Jr. (D-Calvert) at the time allowed the full chamber to debate the bill anyway. Senators instead passed a measure that tightened evidentiary standards in capital cases.

Before Thursday’s committee vote, senators deleted a provision that would have provided $500,000 a year to help crime victims.

The provision became controversial because opponents of the repeal questioned whether it would undermine their ability to petition the issue to the ballot. Under the state constitution, bills that include appropriations are not eligible for a public vote.

The move to delete the provision came despite an advisory letter circulated by state lawyers this month that reasoned that it is “more likely than not” that a court would allow a petition effort to go forward because the appropriation is not central to the repeal bill.

Frosh said O’Malley had pledged to provide the funding whether it was mandated in the bill or not.

On the gun control bill, the committee held firm in backing the core of O’Malley’s agenda.

The committee took several steps to lessen the burden of the new licensing process on gun buyers. It halved the cost to $50, halved the required gun training course from eight hours to four hours, and doubled the renewal time to 10 years.

The committee also tightened O’Malley’s provisions on mental health, prohibiting anyone involuntarily committed to a public or private mental health facility for any length of time from purchasing a gun.

That tougher measure would have prevented the University of Maryland graduate student who police say shot two of his roommates, one fatally, this month from legally purchasing the weapons he obtained after he had been committed to a private psychiatric facility. As introduced, O’Malley’s bill would not have stopped the purchases.