In the past six months, at least 30 states have considered more than 75 bills targeting companies that hire undocumented immigrants. So far, 44 have been enacted, while a handful have been vetoed and several are awaiting a governor's pen, according to the National Conference of State Legislatures.

In applying pressure to employers, the individual measures are spotty: They lay out hiring requirements for public agencies, for example, or for businesses with state contracts. But collectively, they signal Washington that many states are impatient for reform. Such enforcement efforts add up to the broadest assault on employers in years, experts agre

Traditionally, the attitude has been that immigration is a federal issue and doesn't belong in discussion of state issues. These legislative efforts are changing that traditional wisdom.