The battle over whether Minneapolis voters can weigh in on a $15 minimum wage proposal will go to the Minnesota Supreme Court next week.

The state's highest court will hear the case on Aug. 30, following an appeal by the city of Minneapolis over a Hennepin County judge's earlier ruling. At issue for the court: whether a proposal to raise the city's minimum wage can be posed to voters this November as an amendment to the city's charter.

Advocates for higher wages, including the groups 15 Now Minnesota, Centro de Trabajadores Unidos en Lucha and Neighborhoods Organizing for Change, successfully led a petition drive to get the issue sent to voters. But the Minneapolis City Council, following the advice of City Attorney Susan Segal, voted to keep the issue off the ballot. Attorneys for the city contended that a change in the minimum wage would need to be set by a vote of the council on an ordinance, rather than through a charter amendment.

After hearing arguments from both sides, Hennepin County Judge Susan Robiner ruled in favor of the advocates, ordering the proposal to be put on the ballot. A day later, city officials appealed Robiner's decision — and put in a request that the case be sent directly to the Minnesota Supreme Court, so that it would be heard quickly.

The city faces a tight deadline: Items to be placed on the ballot for the November election are to be submitted to Hennepin County by Aug. 26. Ginny Gelms, the county's elections manager, said the county will be able to afford the city some flexibility; a decision reached by Sept. 1 or 2 should be timely enough to ensure that an item could be placed on the ballot and go through a proofing process before being printed in time for absentee voting to open Sept. 23.

In a statement released after the city filed its appeal on Tuesday, Segal said the city maintains its position that the issue comes down to a clear legal conflict.

"We remain of the strong conviction that the petition to place a minimum wage ordinance on the ballot for inclusion in the city's charter is in conflict with Minnesota statutes and the Minneapolis charter, which contains no provision allowing such initiatives," she said.

Advocates, meanwhile, say they are preparing to launch a citywide campaign, from knocking on doors to staffing phone banks. At a rally and news conference Tuesday, 15 Now Executive Director Ginger Jentzen warned that supporters of the wage hike would consider an appeal from the city as a signal of its position on the broader topic of wages.

"The City Council appealing this decision amounts to continuing to defend poverty wages," she said.