Under normal conditions, I'd agree. However, when a company undergoes bankrupcy, the stockholders take it in the shorts, as do creditors. (In GM's case, bondholders as well). Why should they be able to carry forward tax credits when they don't carry forward debt? This is especially galling of the companies that got TARP funding.
Everyone gets screwed but the unions. Nice.
I guess it would depend on the type of bankruptcy, and I can't remember if the old GM was dissolved, or just restructured. GM still does have lots of debt and obligations. They still have a massively underfunded pension, which is a major cause of much or their debt.
In any case I don't see why the government should get to collect more in taxes just because I company had to restructure. Otherwise you are encouraging the government to step in and wipe out companies debt with private parties so they can wipe out the tax credits as well.
This wasn't a normal bankruptcy. It was a huge bailout for the unions, which should have gotten the politicians that were paying off their contributors tossed in jail for a very long time.