As with other questions of constitutional law, the key to Shelby County is, “who decides?”  Congress has concluded that preclearance remains necessary and that the coverage formula based on data from 1964-1972 remains an appropriate way of distinguishing between the areas that must undergo preclearance and those for which preclearance is unnecessary.  Nobody contends that Congress’s coverage formula is perfect; it undoubtedly is both overinclusive and underinclusive in identifying the areas that are most prone to voting discrimination.