At least 30 state Legislatures are considering bills that would require drug testing for welfare recipients.
Proponents say it would save the states money if drug users are booted from the programs. They say taxpayers should not be paying for the recipients' drugs.
But critics say that the cost of the tests would often outweigh the savings. They also point out that some courts have ruled that such requirements violate the Constitution's ban on unreasonable searches.
Critics also worry that the measures will inadvertently harm children, who are the beneficiaries of the bulk of welfare funds. Bills in Florida, New Mexico and elsewhere would allow children of parents who fail drug tests to continue receiving their share of the benefits through a third-party caregiver.