TPTB have dug in their heels, rather than follow in Ann Arbor's footsteps.
While voters in Colorado, Washington, and Massachusetts celebrate the reform of those states' marijuana laws, residents in two Michigan cities are learning that marijuana ballot initiatives are only as effective as the government wants them to be. In Flint and Detroit, popular ballot measures decriminalizing the possession of small amounts of pot have been rendered toothless by resistant city governments.

"Dead silence." That's how marijuana reform activist Tim Beck described the response of Detroit's mayor, city council, and police department to the Nov. 6 passage of a ballot initiative decriminalizing marijuana possession. Three weeks after voters expressed their will, "no member of the media seems able get any kind of answer one way or another," Beck adds.
On Nov. 7, the Detroit City Council—which months before had sued to block the decriminalization measure from appearing on the ballot—called voters' attempt to scale back the drug war "illegal" and a "waste of time."
...
That same day, the city of Flint released a press release calling the passage of its own decriminalization measure "symbolic in nature."
That would be news to Ann Arbor, which decriminalized marijuana in the 1970s, and Grand Rapids, which is implementing their new marijuana ordinance.

What recourse do the citizens have? They can appeal to neither the state nor FedGov, since both entities would side with the city council.

It will be interesting to see a suit filed in any branch of the court system. The judge will have a hot potato in his hands.

Where's this headed? How will it be resolved? Any guesses?