The federal government crafts the immigration laws. The question is, though: are states and businesses the federal government's personal army? Should states and businesses help enforce laws they don't directly have any power over? I can understand things like handing over illegal immigrant criminals to the federal authorities, but expecting states and businesses to dedicate their resources to locating, detaining or discouraging "noncriminal" illegal immigration is a bit much, especially since illegals are often popular in certain local communities, for ideological, tribal or economic reasons.