Supporters of a $15 minimum wage in Minneapolis say they’ll deliver 20,000 petition signatures to City Hall this week — and are confident they have the legal right to put the issue on the ballot this November.

Organizers need 6,869 verified signatures to get the issue on the ballot. But they’ll also have to convince the City Council of two key legal points: that the city has the legal standing to raise wages on its own, and that it can be done by amending the city’s charter, which lays out the framework for how city government operates.

Members of the groups 15 Now and Neighborhoods Organizing for Change laid out their legal arguments on Monday during a media conference call that featured the analysis of two attorneys. Both said they are confident that a higher minimum wage in Minneapolis would stand up to legal challenges.

“We found that the city of Minneapolis has the power to adopt a local minimum wage through its general welfare powers,” said Laura Huizar, a staff attorney with the Washington, D.C.-based National Employment Law Project. “It has broad power to address the health, safety and well-being of its residents.”

Huizar, whose organization has assisted in minimum-wage efforts around the country, said Minneapolis is now part of a much larger movement that includes 30 cities that have adopted local minimum wages higher than those required by the state. At least a half-dozen cities — Washington, D.C., Los Angeles, San Francisco and Seattle among them — have raised the minimum wage to $15, as have the states of New York and California. A similar wage increase is waiting for the governor’s signature in New Jersey.

She said other changes made by charter amendment in Minneapolis show there is room for an issue like the minimum wage. Two years ago, for example, voters weighed in on a charter amendment related to the sale of alcohol in some restaurants.

Huizar also noted that Minnesota does not specifically prohibit cities from passing local minimum-wage laws. In recent weeks, however, some Republicans in the Legislature have said they want to make an overriding law a priority, and some business groups have indicated support for such a move. Such a law could also affect Minneapolis’ new sick-leave ordinance.

The attorneys said the interest in such a law could benefit the legal arguments of those supporting a higher minimum wage. Huizar said that if lawmakers are arguing the need for a law, it’s a good indication that they don’t think current law would stop Minneapolis from acting alone on the issue.

Karen Marty, a local attorney who has worked with city governments and their charters, said she believes the minimum-wage advocates are also on solid footing when it comes to the question of which issues can be considered as charter amendments. In Minneapolis, only the council has the power to make specific ordinances, while citizens can propose and vote on amendments to the charter if they gather the required number of signatures.

Minneapolis City Attorney Susan Segal has not weighed in on either legal question, but the chairman of the city’s Charter Commission has said he does not believe the minimum-wage issue would be a proper charter amendment proposal.

Marty said the rules for what is or isn’t a charter amendment are broad, and other court cases have provided some guidelines.

“There is case law that’s quite clear that if a group of citizens does put together enough petitions for a proposed charter amendment, that proposal must go on the next ballot,” she said.

Members of 15 Now and Centro de Trabajadores Unidos en Lucha plan to hold a rally at City Hall on Wednesday before dropping off the petition signatures. Then, the Charter Commission will accept the petition and refer it to the City Clerk’s Office for a formal review. That process will determine whether the group has enough signatures from registered voters to refer the issue to the council.

Last week, organizers hoping to get a separate issue on the ballot — a charter amendment that would require Minneapolis police to carry professional liability insurance — learned that the majority of the 14,602 signatures they submitted to the city were invalid. After an extensive review process in which they tried to match signatures with official voting registration records, city staff members found just 6,360 signatures that passed muster.

The Committee for Professional Policing, the group that submitted the petition, now has until July 5 to come up with another 509 signatures to meet the required threshold.