"Any reorganization of the decades-old Central States Pension Fund would take months and would probably be a brutal battle as workers, retirees, union leaders and employers all seek to protect competing interests.... [The] plan has caused consternation for many years, because if it failed, it could wipe out a federal insurance program that now pays the benefits of a million retirees. If the reorganization ultimately proves successful, however, it could serve as a model for other retirement plans with similar, seemingly intractable financial problems."