so, if I understand this correctly, when local governments do this it's usually the interest that fukks them over and essentially puts them on a treadmill
Im not really that familiar with the municipal bond market, but I think you are correct. If a city or state is having budget problems and can't service the interest payments fully, that would lead to a default. The Federal government has the advantage of being able to print as much money as it wants to services its debt, but cities and states do not. I would think New York would be able to handle its debt obligations, though, so I don't think it's that big of a worry. When government revenue starts shrinking dramatically, like in Detroit, that would probably lead to a case where it would be more and more difficult to roll over debt.
Again, not really 100% on this market, so take what Im saying with a grain of salt.