Maryland Gov. Larry Hogan, center, prepares for a photo during a bill-signing ceremony in Annapolis on April 12. Seated with him are Senate President Thomas V. Mike Miller Jr., left, and House Speaker Michael E. Busch. (Patrick Semansky/AP)

Maryland’s House of Delegates voted unanimously three years ago to cap the state’s yacht tax. This year, 25 House lawmakers voted against renewing the cap after a small group of Democrats argued that the state doesn’t need to protect wealthy boat owners from tax hikes.

That opposition wasn’t enough to keep the measure from advancing to the desk of Gov. Larry Hogan (R), a popular centrist whose election 18 months ago coincided with Republican gains in the Democratic-majority legislature.

But it highlights the slow pace of progress for Maryland’s newest progressive lawmakers, an assertive and largely young group of legislators who are trying to nudge their party leftward.

“A lot of us came to Annapolis to make change,” said freshman Del. Jimmy Tarlau (D-Prince George’s), who helped organize an unofficial caucus of new legislators that met weekly during this year’s General Assembly session. “With the Republican victory in 2014, a lot of us thought maybe something was missing, and that we could strengthen the Democratic message moving forward.”

“A lot of us came to Annapolis to make change,” said freshman Del. Jimmy Tarlau (D-Prince George’s). (Courtesy of Del. Jimmy Tarlau)

At times, the newest Democratic House members have put themselves at odds with more-centrist colleagues and Democratic leaders as they try to define the soul of the state party with liberal bills and votes. But progressives in the chamber, where Democrats hold 91 of 141 seats, are cheering them on.

“We’re glad they’re here,” said Del. Ariana B. Kelly (D-Montgomery), a second-term lawmaker. “The way things have been done in the past is not the way they’re choosing to do things.”

One sign of the new dynamic emerged when progressives fought a bill to prohibit public marijuana use. Advocates said unwanted exposure to the smoke created a public health risk and a nuisance. Critics countered that the change would roll back the state’s recent efforts to decriminalize low-level pot activity — efforts aimed in part at reducing the number of African Americans put in jail.

The House passed the measure with broad support among Democrats, but some freshmen argued against the bill, drawing the ire of centrists such as Del. C.T. Wilson (D-Charles).

“I can’t stand a paternalistic mind-set,” said Wilson, who supported the bill and is African American. “If I hear one more young white Democrat tell me about saving black men, I’m going to pop. I grew up as an orphan. I know what it’s like to have a tough life. You don’t have to make smoking weed a color thing.”

The intraparty debates pose a challenge for House Speaker Michael E. Busch (D-Anne Arundel), who must ensure that the legislative process runs smoothly in his chamber while still representing his increasingly center-right district.

In some respects, Busch and the growing progressive wing of the House have found ways to complement each other. This year, the speaker rallied enough Democratic votes to override Hogan’s veto of a bill that allows felons to vote while on parole or probation — a bill sponsored in the House by freshman Del. Cory V. McCray (D-Baltimore).

“There’s a generational shift and somewhat of an ideological shift with the freshmen,” said Del. William C. Smith Jr. (D-Montgomery), a first-term lawmaker. (Courtesy of Del. William C. Smith)

Busch also allowed a floor vote on a bill that would require Maryland employers to provide paid sick leave to their workers, a measure that stalled repeatedly in past sessions. Progressive Democrats made sick leave a top priority for 2016, seeing an opportunity to embrace President Obama’s agenda and distinguish their party from the GOP on an issue that affects working-class voters.

“I think a lot of us in the rank and file were hoping to see that we define ourselves against the Hogan agenda,” said freshman Del. David Moon (D-Montgomery).

Progressives helped launch a plan to link the sick-leave bill to a major tax-relief proposal, in hopes of winning support from Hogan and from less-liberal lawmakers worried that it would hurt small businesses. But the measure never advanced in the Senate.

The progressive freshmen have also proved less deferential toward committee leaders than their predecessors in recent years, voting in substantial numbers against bills such as one that would allow salons to avoid unemployment insurance for contracted nail technicians and another that would allow utility companies to pass along some of their environmental-cleanup costs to ratepayers.

“People are paying close attention to bills to see if they are truly consistent with our values,” Kelly said. “There’s a more robust conversation in our party about whether any bill should really be coming out of committee.”

One key victory for progressives this year was the passage of a bill Kelly sponsored that prohibits insurers from charging co-pays for contraceptive drugs and procedures, including vasectomies. Advocates have described the new law as the most comprehensive contraceptive requirement in the nation.

“There’s a generational shift and somewhat of an ideological shift with the freshmen,” said Del. William C. Smith Jr. (D-Montgomery), a first-term lawmaker. “It’s a growing pain within a party that is adjusting itself to new ideas and perspectives.”

Some committee leaders have found ways to accommodate the newcomers, including by calling on freshman lawmakers to defend bills during floor debates, a rarity in the legislature.

The House Appropriations Committee chair, Del. Maggie L. McIntosh (D-Baltimore), assigned Del. Brooke E. Lierman (D-Baltimore) to argue on behalf of a measure that would require the Hogan administration to score transportation projects before deciding which proposals to fund and to explain its reasons for picking lower-ranked plans ahead of those that score higher.

Both chambers ultimately passed the bill and overrode Hogan’s veto.

Kelly said progressives need to continue pressing hard for their priorities while being mindful that their successes could put Democrats from more-centrist counties, such as Anne Arundel, Baltimore and Howard, in an awkward position.

Democrats already lost members of the General Assembly in the 2014 election, when the GOP picked up nine seats in swing districts — seven in the House and two in the Senate. Those losses, along with an influx of progressive-minded freshmen from Democratic strongholds, have made the caucus more liberal.

“There aren’t many blue-dog Democrats left. I’m one of the few,” said Del. Eric M. Bromwell (D-Baltimore County), adding that he’s seen an increase in contentious proposals advancing in the chamber — such as paid sick leave and felon voting.

“There were bills that made it to the floor that wouldn’t have made it in the past — bills that might put people in a bad position come election time,” Bromwell said. “But there’s really no moderate contingent to be protected now.”

Some of the newest House members say Maryland should shift even further to the left, arguing that other heavily Democratic states such as California, Massachusetts and New York have been more forward-thinking.

But Bromwell contends that Maryland is right to be less liberal than those other states.

“California was issuing IOUs instead of tax returns not too long ago,” he said, referring to the state’s 2009 decision to suspend refunds as part of a plan to eliminate ballooning debt and a nearly $30 billion budget deficit. “Maryland has a triple-A bond rating. How many other states can say that? You have to legislate carefully.”

Wilson said staunch progressives risk losing touch with Marylanders as a whole if they move too far left.

“We have a Republican governor, and people are very pleased with him,” he said. “Our state is centrist, and I hope the General Assembly catches up to that. I think it will, because people’s votes are going to start counting with the election coming up in two years.”

Arelis R. Hernández contributed to this report.