Detroit’s bankruptcy filing has mayors, citizens and taxpayers of other cities watching with interest. Time magazine’s cover story this week focuses on Detroit and asks, “Is your city next?”

While some of Detroit’s troubles are unique, the city also has challenges much like those in many other cities.

Bankruptcy lawyer Karol Denniston, quoted in The Week magazine, said, “Detroit is going to be a huge test kitchen.”

With its historical dependence on one industry, Detroit has taken hits over the years as the auto industry went through boom and bust cycles. But city management did nothing to adapt to new realities.

Philadelphia, Portland, Ore., and Chicago, whose debt rating was just downgraded, are often mentioned as cities with the most unsustainable finances. But there are many U.S. cities, large and small, teetering near the brink — needing to cut public safety costs as well as pension and health care expenses for employees and retirees.

One commentator noted that when Detroit automakers were doing well, city leaders agreed to give public-sector unions wages and benefits that could not be sustained when times got tough.

Detroit woes have been made worse by decades of mismanagement and corruption in City Hall. Former Detroit mayor Kwame Kilpatrick. who went to prison for perjury and now faces sentencing after being found guilty of various public corruption charges, made the city’s financial picture darker by selling $1.4 billion in bonds, then allowed much of that money to be directed to risky investments.

As automakers struggled, Detroit shrank, but union leaders and the politicians they put in office refused to trim the workforce. Detroit now has a much higher ratio of municipal workers to citizens than that of comparable-sized cities.

When sales for the Big Three automakers slowed dramatically during the financial crisis of 2008-09, General Motors and Chrysler faced bankruptcy. They survived with the help of a federal bailout, but the real prospect of bankruptcy allowed the companies to get their finances in order, including reducing long-term pension and health care costs.

In the private sector, union demands have to be weighed against company profits and survival. If wages and benefits threaten the company’s survival, the employees risk losing it all. Even knowing that fact, some union leaders press too far, and the company fails, taking jobs and benefits with it.

In the public sector, the labor constraint provided by the risk of pushing the employer too far, did not exist, until recently. But it does, or should, now.

Detroit is not the first municipal bankruptcy. There have been a handful of others, but Detroit is the biggest. And it will be watched closely.

Time magazine’s story argues there’s a bright side to Detroit’s bankruptcy filing, calling it a wake-up call to other cities whose finances, particularly long-term costs related to pensions and health care must be fixed.

But the lessons of Detroit are not just for other cities. States, including Pennsylvania, face huge pension gaps. Illinois has the worst pension gap, with pension liabilities equal to 241 percent of state revenues. But politicians in Harrisburg are responsible for putting Pennsylvania in the top 10 worst pension messes.

So the message from Detroit should be heeded in other cities, but also in state capitals across the country.

There are no easy fixes and the best way out of the mess is to share the pain between taxpayers, municipal and city workers. That will likely mean higher taxes, but it should also mean workers contributing more to their pensions and health care coverage while also seeing some modest trimming of benefits including later retirement ages.