In Detroit Ruling, Threats to Promises and Assumptions Cycling past a Detroit wall on Tuesday. A judge's ruling has given distressed cities leverage to backtrack on pension promises. Someday, Detroit's bankruptcy may well be seen as the start of an era of broken promises. For years, cities have promised rock-solid pensions without setting aside enough money to pay for them, aided by lax accounting practices, easy borrowing and sometimes the explicit encouragement of labor unions. Officials were counting on rich investment gains to fill the holes; unions and their retirees were counting on legal provisions - like Michigan's Constitution - that said pensions were unassailable and that benefits would always be paid, whether through higher taxes or budget cutbacks elsewhere. But a bankruptcy judge, Steven W. Rhodes, threw a wrench into that thinking on Tuesday, ruling that pension benefits could be reduced in a bankruptcy proceeding. The decision recast the landscape and gave distressed cities leverage to backtrack on their promises. "Last night, as a public employees" union leader, you went to bed thinking, "My workers" pensions have special protection; I can continue to play hardball," " Karol K. Denniston, a lawyer with the firm Schiff Hardin who has been advising residents of California cities on fiscal issues, said Tuesday after the judge issued his ruling. This morning you woke up and found yourself in a new world. Public employees" unions are already fighting back, though not against the chronic underfunding of their benefits. They are fighting the notion that at some point, the state protection of benefits does not hold. Detroit's biggest municipal union, the American Federation of State, County and Municipal Employees, or Afscme, swiftly asked permission to appeal directly to the United States Court of Appeals for the Sixth Circuit, rather than Federal District Court, citing the wide public interest in the case. Officials of Detroit's pension system said Wednesday that they planned to appeal as well. "The state Constitution represents the people's will," they said in a statement. That will cannot be ignored or subverted because it's financially convenient to do so. Afscme leaders were also girding for battle in California, Florida and Illinois - places where public pension costs are rising beyond the local population's willingness to pay, prompting cutbacks, whether in bankruptcy or not. They and other union officials argue that their members bargained away potential salary increases in favor of pensions, so cutting them now would be like refusing to issue paychecks at the end of the workweek. "It's a horror film," said Anders Lindall, a spokesman for Afscme in Illinois, where the state legislature voted Tuesday to cut back retirees" cost-of-living adjustments as part of a broad effort to bring the state's pension system into balance. Illinois, like Michigan, has an explicit reference to protecting public pensions in its Constitution. Sharon Levine, a lawyer who helped lay out the unions" case before Judge Rhodes, warned that his decision would "be a road map for governors across the country to use Chapter 9 to create a self-created emergency." Fiscal hawks argue that states and cities already have a pension emergency, just not an easy one to see. Economist after economist has begun to argue in recent years that trillions of dollars are missing from state and local pension systems, but the shortfall is obscured by murky accounting. Governmental accounting rules, in turn, were written differently from corporate ones on the thinking that a city differs from a company. One big difference is that companies go bankrupt by the thousands but cities are thought to last forever, supposedly giving them infinite time and little reason to disclose pension values precisely. Detroit illustrates the flaw in that thinking, but not just since Tuesday's ruling. Its painful decline has been happening for decades. As city workers continued to build up their benefits over the years, the cost of the pension promises grew beyond the means of the city's shrinking tax base. In 2005, the city needed more cash for its pension funds, so it tapped the municipal bond markets for $1.4 billion. Detroit, by that time, had already reached its legal borrowing limit, but its financial advisers were able to structure the deal to make it appear as if it did not add to the city's debt. The unions signed on because the mayor at the time, Kwame M. Kilpatrick, warned that the only other option was to lay off 2,000 workers, many of them union members. The prospectus's description of the constitutional pension protection made it seem as if the city was simply complying with its mandate.