Istalia currently provides a tax credit for families who send their children to college. Faced with dire financial straits, Istalia has decided to eliminate this tax credit but to continue to extend (or “grandfather”) it to families currently taking advantage of it.

Given that such grandfathering will lead to inequities between families of current and future college students, and that the grandfathering will be costly for the government relative to the full elimination of the tax credit, why would Istalia choose to grandfather?