MINNEAPOLIS (WCCO) — Days after the Minneapolis City Council voted not to include a ballot initiative for an amendment to the city charter raising the minimum wage to $15 an hour, advocates for the measure are making good on a promise to strike back.

Local activists filed a lawsuit in Hennepin County Court Monday in an effort to compel the city to include the initiative on the ballot before it’s finalized for the November election.

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On Friday, the Minneapolis City Council rejected a ballot initiative that would amend to the Minneapolis City Charter to set the minimum wage at $15 an hour. Activists collected more than 20,000 signatures on the petition.

In the Aug. 5 vote, the city council passed a resolution in agreement with the findings of the city attorney, who said the measure wasn’t a valid amendment to the city charter. Amendments, the city attorney argued, are limited to addressing the “structure, authority and procedures” of the city government, not the laws and regulations that the government creates.

After the vote at the city council meeting, activists staged a walkout, chanting “See you in court!”

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In the lawsuit filed with the help of the nonprofit National Employment Law Project, the plaintiffs argue that the city offered no legal precedent for their position. The lawsuit also points out precedent for their cause, including a Minnesota Supreme Court case where the justices upheld a charter amendment in St. Paul about workers’ rights that, the plaintiffs argue, had little to do with the “structure, authority or procedures of local government.”

After the council voted the measure down on Friday, council members issued a directive to City Coordinator staff to conduct research about an ordinance raising the minimum wage, and its possible effects on the city. The directive asked the staff to submit their findings and recommendations by the second quarter of 2017.

Ginger Jentzen is with the group 15 Now Minnesota, which advocates for raising the minimum wage. She says says the 100,000 minimum wage workers in Minneapolis can’t wait for the city to research, recommend, write and pass an ordinance.

“It lays out a nonspecific timeline. It doesn’t specifically propose a process,” she said of the city council’s staff directive. “The city charter amendment is the only concrete proposal on the table right now.”

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Several city council members did not immediately return a request for comment.