San Francisco’s new cannabis legislation — which was supposed to be a shining achievement for the Board of Supervisors — has become the latest sign of a feudal style of politics that has hindered the board this year.

Historically, the board has split along moderate and progressive lines. But this year it’s become more fractured, with 11 supervisors often emphasizing concerns related solely to their district over citywide policies. The result: Few pieces of significant legislation have been enacted.

“I can definitely see fragmentation, division and not really paying attention to the big picture,” said former Supervisor David Campos, now the chairman of the San Francisco Democratic Party. He and another former supervisor, state Sen. Scott Wiener, intervened last week in the debate over licensing recreational cannabis businesses, which had been overrun by parochial politics, with several supervisors demanding dispensary caps or bans in their neighborhoods.

If all the board members got their way, the cannabis industry would be outlawed in most of San Francisco, Wiener said.

But that’s only one example of a balkanized board fixated on neighborhood interests that slow down the legislative process.

“Basically, the city has evolved to the point that supervisors act as manor lords of their realm,” said David Latterman, principal at the consulting firm Brick Circle Advisors, who worked on legislative campaigns for Wiener and state Assemblyman David Chiu, among others. “There are few people on the board who are thinking about the big picture.”

The supervisors’ flagship achievement this year was an inclusionary housing ordinance designed to keep low- and middle-income people in the city. It passed unanimously after months of bickering.

The board also approved a major housing-density bill that Supervisor Katy Tang introduced last year, as well as Supervisor Malia Cohen’s law banning flavored tobacco, which was suspended after opponents gathered enough signatures to force a referendum.

That’s a short list compared with last year, when a board with a different composition passed at least a dozen big laws. They included the creation of the Department of Homelessness and Supportive Housing, a ban on Styrofoam, a law extending paid family leave, a sanctuary-city ordinance to protect undocumented immigrants, a law promoting citywide construction of in-law units, a law mandating trigger locks and locked storage for guns in homes, a law barring the leasing of city-owned land in the Central Valley for fossil fuel extraction, and an ordinance prohibiting the sale of tobacco products to people younger than 21.

The supervisors accomplished all that while putting together ballot measures to create sales taxes for transportation and homelessness, fund street tree maintenance, add a public advocate’s office, and provide services for seniors and disabled people.

San Francisco’s political experts have varying theories to explain the slump. Richard DeLeon, a professor emeritus of political science at San Francisco State University, wonders whether a lack of political ambition is to blame, given that it’s not an election year. But Latterman argues, to the contrary, that the board may suffer from too much ambition — several supervisors are expected to run for for higher office, and it may not be in their interest to push bold ideas that generate controversy, he said.

Jason McDaniel, a political science professor at San Francisco State, said that in past years, supervisors were motivated by ferocious competition between the progressive and moderate wings, which “created a lot of incentives to (produce) legislation.”

With the departure of strongly partisan lawmakers like the moderate Wiener and more liberal Campos, those factions appear to be weakened. The new supervisors have a less-confrontational style of governing, choosing to hold hearings, sponsor resolutions and form task forces rather than pass laws.

Without leadership in the moderate and progressive camps, the supervisors are returning to immediate concerns — which means squabbling over resources for their districts. This limited focus can make it difficult to get majority agreement on anything. Supervisors introduce proposals only to pull them back or amend them to the point of being unrecognizable.

For example, fights over the city’s budget erupted in City Hall in June, as each supervisor clawed for money to fund pet projects and causes. The board ultimately passed a budget, but only after days of bruising, tearful arguments — some in the middle of the night.

Some other examples:

•Supervisor Norman Yee’s sidewalk robot restrictions and Supervisor Jeff Sheehy’s prohibition on glass bottles in city parks advanced to the full board, only to be kicked back to committee because they lacked support.

• Yee and Supervisor Hillary Ronen withdrew an ordinance to put property crime units in each district police station after failing to persuade Police Chief Bill Scott, whose support was critical, to sign on. The two supervisors resurrected the idea as a nonbinding resolution, which has no force of law.

• At times a desire to come out on top, no matter what, has taken precedent. When Supervisor Mark Farrell introduced a bill in April to protect tenants from fraudulent owner-move-in evictions, he quickly met competition from down the hall — in the form of a near-identical proposal by progressive Supervisors Aaron Peskin and Jane Kim. It took 3½ months to merge the two bills.

“I think it’s true that the board isn’t passing much monumental legislation,” said Ronen, acknowledging that most supervisors — herself included — are focused on their individual neighborhoods.

Ronen sees that as a call of duty rather than a problem.

“When I ran for office, I promised my constituents that I would be laser-focused on my district,” said the supervisor, who represents the Mission, Bernal Heights and Portola areas, where many residents are angry about sidewalk tents and a recent spike in burglaries.

She said she’s spent the bulk of her first year scouting out properties to open new navigation centers for homeless people, interceding in development deals gone awry and cleaning up major public areas, like the 16th Street BART plaza.

That approach “at times has not made me very popular with my peers,” Ronen said, recalling how she was attacked during budget talks for requesting an additional aide to help solve her district’s problems.

Board President London Breed agreed with Ronen that supervisors should prioritize the people “who elected us to this office” — which means slogging through a lot of cranky emails about construction, Muni and needles on the ground.

“I didn’t come to the Board of Supervisors to just be a policymaker,” Breed said. “I was more excited about being able to do things for my community.”

Some observers criticize the board for letting day-to-day constituent services interfere with their legislative agendas.

“If you just want to serve the community, then there’s plenty of volunteer opportunities,” said former Supervisor Chris Daly, a progressive who was known for starting knock-down ideological spats, but who also produced scores of bills during his 10 years in office.

This year’s board has four new members — Ronen, Sheehy, Sandra Lee Fewer, and Ahsha Safai — who may take a while to acclimate to the job, said Yee, who joined the board in 2013.

“When I first came on, I thought, ‘What do these people do? Stay up all night thinking about legislation?’” Yee said, referring to his more senior colleagues.

But Yee also praised the new supervisors for voting individually, rather than in blocs.

Latterman was less understanding. He noted that San Francisco is a city of disconnected neighborhoods, and said residents are craving leaders who can bring everyone together. They’re not getting that from the board, Latterman said.

“There’s a malaise in the city right now,” he said. “And the question is, who is going to break through that? Who is going to think about the big picture?”

One City Hall insider who didn’t venture an opinion on the board’s accomplishments this year: Mayor Ed Lee, who would not comment for this story.

Rachel Swan is a San Francisco Chronicle staff writer. Email: rswan@sfchronicle.com Twitter: @rachelswan