As they took full control of the state legislature for the first time in more than two decades, Virginia Democrats promised bold changes to the criminal justice system.

A month into Democratic leadership and halfway through the legislature’s whirlwind annual session, many advocates say lawmakers have fallen short on those promises.

“It’s disappointing to see that some of the criminal justice reforms that were spoken about in the campaign have been dropped,” said Richard Johnson, Richmond’s capital defender. “We’re not quite getting what we thought we were getting.”

The rift started when Del. Michael P. Mullin (D-Newport News), who also serves as a prosecutor, was appointed head of the subcommittee that hears proposals to change the criminal code. A group of activists from the NAACP and other groups sent a letter to incoming House Speaker Eileen Filler-Corn (D-Fairfax) arguing that “appointing . . . a current prosecutor without a strong track record on these issues is a conflict of interest that we strongly oppose.”

They say that they never got a response and that Mullin and House Courts of Justice Chairwoman Charniele L. Herring (D-Alexandria) have proved resistant to many of their proposed changes.

They point to an effort to legalize marijuana that was passed over in favor of a decriminalization bill that applies only to adults and imposes a fine for use.

Some Democratic lawmakers share that disappointment over marijuana legislation.

“I understand the need for some people who want incremental change, but [marijuana] is an area where we could go bold,” Del. Jennifer D. Carroll Foy (D-Prince William) said. “There are other states who are doing this and doing it well.”

Bills to reinstate parole, abolished in Virginia in 1995, were deferred for a year of study, although measures that would extend it to a limited class of prisoners have advanced. Legislation that would make it easier to expunge a criminal record was also put off. Bills to allow juries more flexibility in sentencing, vacate convictions because of changed scientific evidence, and give people who report drug overdoses immunity from prosecution died.

Claire Gastañaga, executive director of the ACLU of Virginia, said she’s not surprised. In her seven years in Richmond, she said, she’s often found some Republicans easier to work with on criminal justice reform than Democrats who are fearful of being seen as soft on crime.

“It’s not just isolated to this session,” she said.

But Carroll Foy and many other elected Democrats say that overall, it has been a banner year for criminal justice reform.

“We are making revolutionary changes down here in Richmond,” Carroll Foy said. “We’re changing how we do jury trials. We’re being more transparent. . . . We’re adding public defenders’ offices.”

Bills have moved forward to ban the death penalty for severely mentally ill defendants, decriminalize disorderly conduct by school students, ban civil forfeiture until a defendant is found guilty and end suspensions of driver’s licenses over court costs. So has a bill that would allow judges to ignore mandatory minimums in sentencing juveniles and another that would let defendants choose sentencing by a judge rather than a jury.

While lawmakers rejected efforts to raise the age at which juveniles can be tried as adults from 14 to 16, they did move to end mandatory adult trials for 14- and 15-year-olds accused of major crimes. Many of those changes were made despite objections from Republicans and the powerful Virginia Association of Commonwealth’s Attorneys.

Party leaders bristle at the criticism and say major reform takes time.

“We’re doing quite a lot, and we’ve done quite a lot,” Mullin said in one hearing. “We’re doing what we promised.”

Major changes, he and Herring argued, should not be waved through by exhausted lawmakers at the end of hours-long committee hearings.

“I just don’t believe in hastily and sloppily doing something so important; it’s just not fair,” Herring said. “We can’t change the world, complete reform, in one session.”

Some of the proposals, Mullin said, were previously “so out of the pale that I never really thought of them before. . . . Maybe we just need some people with PhDs and a little bit more than four hours to work.”

Critics argue that much of what they have proposed is already law in other states and has been under consideration in Virginia for years.

During one debate, Del. Don L. Scott Jr. (D-Portsmouth) noted sarcastically that Virginia would be following “real, real liberal states like Texas.” He added, “Can you explain to me why we need another study to study something that’s already going on?”

Virginia is not among the highest- or lowest-ranked states in terms of overall and juvenile incarceration rates and racial disparity in sentencing, according to data collected by the nonprofit Sentencing Project. But the commonwealth is an outlier in felony disenfranchisement. Only five other states let juries determine sentences, and no other state limits them as Virginia does in what they can know and how they can craft that punishment. Defense attorneys say the higher penalties juries must impose make going to trial too risky for even some innocent people.

“This is the first time we’ve had a trifecta in decades,” said Johanna Gusman of NAACP Loudoun. “It’s frustrating that a lot of things seem to have been given up on before they even tried.”

Because Virginia’s legislative session is so brief, anything that does not pass out of at least one chamber by February has no chance of becoming law for another year. And critics say sending bills to the Virginia Crime Commission for study is not encouraging. A bill that would have expanded its mission and leadership to include more alternatives to incarceration failed.

“When they refer things to the crime commission, that can be a way to push off difficult conversations,” said Kim Rolla of the Legal Aid Justice Center. “Part of the frustration is, we didn’t even have that conversation.”

But some lawmakers said they were optimistic about next year.

“All of the bigger, more transformational bills have been sent off for study,” Del. Lee J. Carter (D-Manassas) said. “And so there’s going to be a huge stack of reports next year, and we will know exactly what we’re doing, and there will be no more excuses.”