The House of Delegates is poised to vote Saturday afternoon on whether to decriminalize possession of small amounts of marijuana, a significant milestone in a long fight to treat the drug as no worse than a minor traffic offense.

A key committee that killed similar plans in the past instead voted 13-8 Saturday morning to deal that would make possession of small amounts of marijuana civil offense with no jail time.

For advocates who have long pressed to stop filling courthouses and jails with minor drug offenders, Saturday morning's vote signals their best hope yet to join more than a dozen other states in decriminalizing possession of pot.

The bargain struck Saturday morning averts what would have otherwise been a prolonged fight on the floor of the House of Delegates, as the Legislative Black Caucus and another Democrats vowed to push the issue before the entire chamber.

The deal paves the way for a bill to reach Gov. Martin O'Malley's desk before the legislative session ends Monday night.

Decriminalization advocates in the House of Delegates mobilized Friday to amend the bill that would have otherwise merely set up a task force to study the decriminalization issue over the next two years.

On the House floor Friday, Dels. Keiffer J. Mitchell Jr. and Nathaniel T. Oaks, both Baltimore Democrats, offered an amendment that would strip out the task force language and instead make marijuana possession a civil offense punishable by a fine. That's what the bill was intended to do when it passed the Senate, but the House Judiciary Committee later changed it into a task force bill. Saturday's action undid that move.

Mitchell told the House he could not in good conscience support a bill putting off a decision on whether to stop arresting people for simple possession when there are significant racial disparities in how the law is enforced.

But Mitchell and House Judiciary Committee Chairman Joseph F. Vallario Jr. agreed to put off a showdown until Saturday. What followed was a round of talks between decriminalization supporters and Vallario, a Prince George's Democrat. Among the critical players were members of the Legislative Black Caucus, which strongly supports decriminalization because African-Americans are arrested for the offense at a disproportionate rate.

The compromise would give decriminalization advocates most of what they wanted. Possession of 10 grams or less of marijuana would no longer carry a jail term and would not appear on a person's record as a criminal offense. Marijuana possession now carries a maximum penalty of 90 days in jail, though prosecutors insist such punishment is rare.

In a concession to committee members who are skeptical about decriminalization, advocates agreed to increase some of the fines and require people under 21 who are caught with the drug to go to court, where they could be ordered into drug treatment, even on the first offense.

People over 21 found with marijuana would be given a citation that they could prepay by mail for the first offense but on the second and third would have to go to court, sources said. On the third, the judge could order the offender into drug treatment or education.

The advocates also agreed to increase the fines for a repeat offense, sources said. Where the Senate bill set a flat fine of $100, the House plan would impose a fine of $250 for the second offense and $500 for the third.

The compromise approved by the House Judiciary Committee Saturday morning is expected to be offered on the floor Saturday as a committee-sponsored amendment.

Sen. Robert A. Zirkin, the Baltimore County Democrat who sponsored the decriminalization bill in the Senate, said he anticipates his colleagues will accept the deal and send the bill to O'Malley.

"I'm excited that this is happening. I'll wait until the balloons drop, but it looks like a lot of members of the House worked exceptionally hard over the past 24 hours to get this done," he said Friday night.

Though O'Malley has been cool toward decriminalization in the past, spokeswoman Nina Smith said he is keeping an open mind. She noted that he signed bills last year lowering possession penalties and setting up a medical marijuana program.

That program has not gotten off the ground because it relied on academic medical centers. The General Assembly is expected to send a new medical marijuana bill to the governor this year, increasing access to the drug to treat serious medical conditions.

Oaks said the statistical evidence has been on the side of decriminalization advocates.

"Seventeen states have already decriminalized and there has been no increase in drug use in teenagers or adults," he said.

In public hearings, the decriminalization effort ran into determined opposition from law enforcement officials, including prosecutors and police chiefs who warned that removing criminal sanctions could make marijuana more available to juveniles and lead to an increased in drugged driving.

Baltimore Sun reporter Erin Cox contributed to this article.

michael.dresser@baltsun.com