And how is bankruptcy going to prevent this from occurring again? Will future politicians still have the ability to grant crazy pensions knowing their term won't endure its negative effects? Not sure what the solution is but I don't think bankruptcy will solve it.
Why should unions have any political zorch? Why must collective bargaining require any amount of state intervention (besides, obviously, protecting individual liberty and property)?
I think the pattern has been established in cities which avoided bankruptcy, like San Jose - you hire a barebone skeleton of public employees, re-negotiate the contracts in light of macroeconomic conditions, and subcontract everything else - those employees are now eligible for 401k or IRA or other more exciting things.
