The legislation, which took effect in 1996, came after a five year battle and several court cases.
It covers a variety of retirement programs, including IRA's, 401(k)'s, federal retirement programs and three types of "non-qualified" plans.
States had argued that taxing former residents was reasonable because the tax had been deferred while people were working in those states. President Clinton and congressional members took the position that retirees should not have to pay taxes to states where they do not live, vote or use any of the states' services.