The California Supreme Court handed down a ruling on Monday that could make it slightly easier for citizens to levy new local taxes through voter-sponsored ballot initiatives.

The ruling rested largely on how the court interpreted sections of the state Constitution impacted by Proposition 218. Passed by voters in 1996, Prop. 218 spells out how local governments may levy new taxes and fees, including the vote thresholds that have to be met to approve proposed taxes.

At the heart of the court’s ruling is the notion that ballot initiatives generated by citizens aren’t subject to the same constraints as local governments.

The lawsuit in the case was brought by the California Cannabis Coalition against the city of Upland (San Bernardino County). In 2014, the Cannabis Coalition began circulating a ballot initiative that would have repealed an existing Upland ordinance banning medical marijuana dispensaries and also would have spelled out rules under which dispensaries could operate in the city, including paying a $75,000 annual fee.

The nonprofit’s initiative secured signatures from 15 percent of the city’s residents, triggering a state law that required Upland officials to either adopt the initiative or put it up to a vote in a special election. After reviewing the proposal, however, the city said it would only require a $15,000 licensing fee from dispensaries. The excess as proposed by the coalition constituted a general tax, the city contended, and therefore could only be decided on in the next general election. The city refused to hold a special election for the proposal.

The group sued, insisting that it was entitled to put its proposal in front of voters during a special election, and that it shouldn’t have to wait until the 2016 general election. At a special election, “it’s easier to get voters out. We thought (the ballot initiative) would have more of a chance to win if it’s in a special election,” said Roger Diamond, the attorney for the Cannabis Coalition.

Diamond successfully argued that regardless of whether the money paid by the dispensaries would be a tax or a fee, “it’s being imposed by the initiative process, so we’re exempt from the requirement that the measure go on the general election. Only tax measures imposed by a government are required for a general election,” under Prop. 218.

The court agreed. Writing for the majority and referencing Homer’s “The Odyssey,” Justice Mariano-Florentino Cuéllar said that the law, as it stands, does not bind voters to the constraints placed on local governments by Prop. 218, which are intended to make it more difficult to create new taxes.

“As Ulysses once tied himself to the mast so he could resist the Sirens’ tempting song , voters too can conceivably make the clear and important choice to bind themselves by making it more difficult to enact initiatives in the future.” Cuéllar said. “The electorate made no such clear choice to tie itself to the mast here.”

The city of Upland, the court ruled, violated state law when it tried to deny a vote on the coalition’s ordinance in a special election. Local governments, by contrast, must always bring proposed general tax increases during a general election, a distinction — as the court clarified — that derives from the law’s intent to give more power to citizens. In short, the court said it should be easier for citizens to propose new taxes, compared with proposals introduced by local governments.

The city of Upland could not immediately provide a representative to comment on the ruling.

The court’s ruling did not touch on the question of whether voter tax initiatives would be subject to a simple majority vote or a two-thirds majority, the threshold governments are subject to when they want to raise a tax for a specific purpose, as opposed to one where the revenue gets put into the general fund.

Darien Shanske, a professor at UC Davis School of Law, said that vote-threshold question would likely have to be decided by a future court case. But he said Monday’s ruling left open the possibility that tax increases proposed by voter initiatives “would be a lot easier to pass during special elections.”

“That could be very helpful for groups capable of organizing and putting a tax increase on the ballot,” Shanske said.

Dominic Fracassa is a San Francisco Chronicle staff writer. Email: dfracassa@sfchronicle.com Twitter: @dominicfracassa