Jazz and wine in the park? Sweet. But forget gin and juice.

For more than a century, going back to before it was called Bayfront Park, the grassy lawn separating downtown Miami from Biscayne Bay has hosted big events.

Athletic games and religious gatherings marked the early 1900s. President-elect Franklin Delano Roosevelt’s downtown speech — and near-assassination — came in the 1930s. These days, the park is probably best known for its concerts and music festivals.

But as downtown has evolved into a bustling office hub and condo community, conflict has seemed inevitable. Now, during a three-month stretch that includes four music festivals, a group of downtown residents is telling the city that something’s got to give — and their secret weapon is booze.

Citing a little-known law, the Downtown Neighbors Alliance says the Bayfront Park Management Trust, created by the city to manage the park, has allowed concert organizers to illegally sell alcohol for years. Last week, when the board approved a contract including alcohol sales for Rolling Loud, a hip-hop festival expected to draw about 40,000 people a day next month, an Alliance member was in attendance to raise the issue.

“I don’t think the board members are aware they’re about to break the law,” Itai Benosh, a resident of the 50 Biscayne building, interjected.

Back in 1990 — at a time when hysteria over gangster rap and heavy metal was at its height — Miami commissioners passed legislation prohibiting the sale of alcohol at Bayfront Park during hard rock, rap and heavy metal concerts. They also threw in music events that require “extraordinary security measures,” which arguably loops in a heavily-policed event like Ultra Music Festival.

But the city disregards the law, arguing that it is probably unconstitutional. On Tuesday, City Attorney Victoria Méndez said dismissively there was nothing problematic with Rolling Loud’s contract.

“It is what it is,” she told Benosh.

But the debate is likely just beginning. Following Tuesday’s vote, the Downtown Neighbors Alliance issued a statement saying the city’s contract “blatantly violates” Miami’s laws. The organization has hired an attorney to potentially litigate the issue, and is now arguing for Bayfront to cut down on the number of big events.

“The continuous use of the Park for massive events disrupts downtown life and results in park closures for months at a time,” the association said.

Miami Commissioner Frank Carollo, who chairs the Bayfront Park Management Trust, gave short shrift Tuesday to the suggestion that alcohol is being illegally served during music festivals, deferring to Méndez. But he said he’s considerate of concerns mounting in downtown over the use of the park.

“Those conversations are welcome,” he said. “And they should be had.”