Court will not recharacterize retroactive SSI as SSD in order to undo recoupment of state aid from retro SSI. Policies in favor of recoupment of state aid from SSI and recoupment of overpaid SSI from SSD are stronger than policy to protect SSD from assignments under §407(a) of the Social Security Act. Anomalous situation - where state aid is recouped if SSI retro is paid before SSD retro, but state aid is not recouped if SSD retro is paid first - does not render statutory scheme unconstitutional because it's rational. Social Security benefits, like SSDI, have been regarded in some contexts as "property" for constitutional purposes. But, Windfall Offset Provision (42 U.S.C. § 1320a-6(a)) does not violate anti-assignment clause and is not unconstitutional because it's rational. Anomalous situation - where state aid is recouped if retroactive SSI is paid before retroactive SSDI, but state aid is not recouped if SSDretro is paid first - does not render statutory scheme unconstitutional. There's no statutory or constitutional violation in provision allowing deduction from SSD retro to recoup overpayment of SSI retro. Provision should be read as an internal computation of how much SSI and SSD a person is due - whereby a prior overpayment of one benefit reduces the amount of the other benefit paid for the same time period.