The Maryland Senate on Monday is scheduled to vote on legislation that would decriminalize the possession of small amounts of marijuana and reduce the fine to a maximum of $100.

If the bill passes, as expected, it would face review by the House of Delegates, where members have raised concerns about a push to place Maryland among the two dozen states changing their marijuana laws.

The House also is considering a measure that would legalize medical marijuana. The measure has support from Gov. Martin O’Malley (D). But with the governor’s gun-control package scheduled for House votes next week, the chamber may not act on the medical marijuana bill before a March 25 deadline to send it to the Senate.

Under the Senate proposal, people caught with up to 10 grams of marijuana, or about one-third of an ounce, would no longer face jail time. The punishment under the current law is up to 90 days behind bars, along with a fine of up to $500.

“We don’t want to wrap people up in the criminal jail system for this,” Sen. Robert A. Zirkin (D-
Baltimore County) said when his proposal was discussed last week.

A Democratic stronghold, Maryland has legalized same-sex marriage and abolished the death penalty. On the issue of marijuana, it has lagged behind states such as California and Washington that have legalized the drug for various uses.

On the Senate floor last week, Zirkin faced minimal resistance from colleagues.

When Sen. Allan H. Kittleman (R-Howard) rose to propose an amendment, he only wanted to add his name as a co-sponsor.

Senate Minority Leader E.J. Pipkin (R-Cecil) said he expected the legislation to pass in the Senate with bipartisan support, even as he said he would vote no.

“What sort of message are we sending?” he asked. “We’ve got zero tolerance for alcohol abuse, we’re moving towards zero tolerance for cigarettes, but this seems like we’re saying it’s okay.”

Under federal law, marijuana remains illegal, which is one reason that Maryland’s Sheriff’s Association and Chiefs of Police Association cite for opposing any weakening of state statutes. By decriminalizing pot, police officials said, lawmakers also may be encouraging use among teenagers.

“We do not support any watering down of any marijuana legislation,” said Vince Canales, leader of the police union in Prince George’s County and a member of the state Fraternal Order of Police. “Until it is legalized, we believe the penalties should be adhered to and enforced.”

State lawmakers across the country are reviewing marijuana laws, as public opinion polls have shown a growing acceptance for legalizing the use of pot for medical and recreational purposes.

Lawmakers in 23 states have drafted bills legalizing medical marijuana, weakening penalties, or imposing taxes on the use of pot, according to the Marijuana Policy Project, a District-based advocacy group.

“Our broader message is that adults should not be punished for choosing a substance that is safer than alcohol,” said Dan Riffle, a lobbyist for the Marijuana Policy Project. “People who use it don’t act like they do with alcohol. It’s not the kind of thing we have to treat like heroin or cocaine or harder drugs.”

Riffle predicted that Maryland lawmakers would legalize pot “in the next three or four years,” taxing and regulating it like alcohol. “The leadership of the legislature is on board with this, more so than in most states,” he said.

O’Malley’s attitude toward the issue appears to be evolving. As Baltimore’s mayor, his police department targeted drug dealers in initiatives that reduced the crime rate. He has opposed past efforts to decriminalize marijuana.

However, in recent days, the governor’s chief health adviser, Joshua Sharfstein, indicated that the administration would support a proposal to allow academic medical centers to distribute marijuana to patients beginning in 2016.

The legislation, written by Del. Dan K. Morhaim (D-Baltimore County) and before the House Judiciary Committee, would require the centers to monitor patients using marijuana and publish their findings, an approach that Sharfstein characterized as cautious enough to allow for an ongoing assessment.

Del. Michael J. Hough (R-
Frederick), a committee member, said he would vote against the legislation because “it’s just part of a bigger push to legalize all marijuana.”

“There’s no legitimate purpose to medical marijuana,” he said. “It’s an illegal drug, the federal government says it is, so either it’s wrong or it’s right.”

Del. Joseph F. Vallario Jr. (D-Prince George’s), the committee’s chairman, said he didn’t have a position on Morhaim’s proposal. As for the bill to decriminalize marijuana, he said he was still weighing the issue.

But he added: “It doesn’t seem like a very good message to be sending to kids.”