Prichard’s pension plan was established by state law during the good times, in 1956, to supplement Social Security. By the standard of other public pension plans, and the six-figure pensions that draw outrage in places like California and New Jersey, it is not especially rich. Its biggest pension came to about $39,000 a year, for a retired fire chief with many years of service. The average retiree got around $12,000 a year. But the plan allowed workers to retire young, in their 50s. And its benefits were sweetened over time by the state legislature, which did not pay for the added benefits.

For many years, the city  like many other cities and states today  knew that its pension plan was underfunded. As recently as 2004, the city hired an actuary, who reported that “the plan is projected to exhaust the assets around 2009, at which time benefits will need to be paid directly from the city’s annual finances.”

The city had already taken the unusual step of reducing pension benefits by 8.5 percent for current retirees, after it declared bankruptcy in 1999, yielding to years of dwindling money, mismanagement and corruption. (A previous mayor was removed from office and found guilty of neglect of duty.) The city paid off its last creditors from the bankruptcy in 2007. But its current mayor, Ronald K. Davis, never complied with an order from the bankruptcy court to begin paying $16.5 million into the pension fund to reduce its shortfall.

A lawyer representing the city, R. Scott Williams, said that the city simply did not have the money. “The reality for Prichard is that if you took money to build the pension up, who’s going to pay the garbage man?” he asked. “Who’s going to pay to run the police department? Who’s going to pay the bill for the street lights? There’s only so much money to go around.”

Workers paid 5.5 percent of their salaries into the pension fund, and the city paid 10.5 percent. But the fund paid out more money than it took in, and by September 2009 there was no longer enough left in the fund to send out the $150,000 worth of monthly checks owed to the retirees. The city stopped paying its pensions. And no one stepped in to enforce the law.

The retirees, who were not unionized, sued. The city tried to block their suit by declaring bankruptcy, but a judge denied the request. The city is appealing. The retirees filed another suit, asking the city to pay at least some of the benefits they are owed. A mediation effort is expected to begin soon. Many retirees say they would accept reduced benefits.