At least that is the case for the healthcare obligations of most states and local areas, though Robert Pozen points out that this is likely to change soon (available here). This is something I discussed when Detroit went through bankruptcy proceedings. Pension and healthcare obligations of the city made a contribution to the bankruptcy, but only because the broader electorate allow it. If we get accurate accounting and compel elected officials to use realistic discount rates there would be a better sense of the amount of these obligations. The proposed accounting changes are a step in the right direction, requiring more transparency and better assumptions.
Taxes & Migration
A recent report out by the Center on Budget and Policy Priorities (available as a pdf here) looks at the connection between state tax rates and migration between states. Or maybe it does not. They find little connection between changes in state tax rates and the migration between states.