Even if St. Paul voters say no to an organized trash collection system next month, the city will have to hold up its end of a five-year contract with haulers, the state’s highest court ruled Wednesday.

The Minnesota Supreme Court’s ruling sets the stage for a stark choice for St. Paul residents Nov. 5: Keep the current system of paying quarterly bills for garbage collection, or pay for it through a hefty hike in property taxes.

“The referendum this fall is no longer a question about whether or not our coordinated collection system will continue, but about how we will pay for it,” Mayor Melvin Carter said at a news conference at City Hall on Wednesday afternoon.

In August, the Supreme Court directed that a referendum appear on this fall’s ballot, rejecting the city’s contention that the contract with haulers superseded that right. But the court on Wednesday affirmed another argument by the mayor: The city was bound to honor the contract with haulers, no matter what voters decided.

Carter warned in August that a “no” vote on trash could lead to hefty property tax hikes, because the city would have no authority to make residents pay their trash bills. The City Council voted 5-2 last month to set the levy limit at 22% so it could bring in enough tax revenue to cover an estimated $27 million for trash collection.

Carter said Wednesday that he’s talked to residents on both sides of the trash issue. “I encourage voters to educate themselves on the impacts of a yes vote and on the impacts of a no vote, and participate in the public process,” he said.

The Supreme Court ruling is the latest twist in the turbulent rollout of citywide trash collection in St. Paul. Until a year ago, residents could choose their own haulers — or none at all — but under the current system, property owners are required to pay for trash collection and are assigned a hauler based on location.

Opponents have argued that organized collection is more expensive and fails to reward those who produce little or no waste. Supporters, including a majority of the City Council and the St. Paul DFL, which endorsed a “yes” vote on the referendum, have countered that the system reduces illegal dumping and truck traffic on city streets.

The referendum will join all seven City Council seats on the Nov. 5 ballot, adding a divisive issue to the off-year election.

Patty Hartmann, a Third Ward candidate who decided to run because of the trash issue, said she wasn’t surprised by the court’s decision and still believes residents have a good reason to vote no. Even though the contract will remain, the ordinance that lays out the rules for organized trash collection will not.

“There has to be something that forces a resident to participate in this, and that’s what the ordinance does,” Hartmann said.

In an interview Wednesday, Peter Butler, one of three plaintiffs in the lawsuit to get the referendum on the ballot, said he’s worried that voters will approve the organized trash system to keep their property taxes from soaring.

Butler said he and the other plaintiffs haven’t discussed next steps, given the Supreme Court decision.

“We’re still advocating for ‘no,’ obviously, and [we’ll] just wait and see what happens,” he said.