CINCINNATI — Years after a wave of construction brought publicly financed stadiums costing billions of dollars to cities across the country, taxpayers are once again being asked to reach into their pockets. From New Jersey to Ohio to Arizona, the stadiums were sold as a key to redevelopment and as the only way to retain sports franchises. But the deals that were used to persuade taxpayers to finance their construction have in many cases backfired, the result of overly optimistic revenue assumptions and the recession. Nowhere is the problem more acute than in Cincinnati. In 1996, voters in Hamilton County...