Policies that exempt high-unemployment places, but not people who face other obstacles to work, selectively acknowledge barriers for only some of the poor. In effect, they suggest that unemployment is a systemic problem in struggling rural communities — but that in poor urban neighborhoods, it’s a matter of individual decisions.

“The hardships of areas that have seen industry leave are very real; the hardships of rural areas that have had jobs automated away are real,” said David Super, a law professor at Georgetown University, who studies public welfare programs. But so are hardships that come from a lack of child care or transportation, he said. “It is troubling that one set of conditions are being taken seriously and another are being scoffed at.”

In Michigan, the proposed exemptions would also effectively protect the constituents of some state legislators who have advocated work requireme nts.

“What’s so galling here in Michigan is the social meaning of this exemption could not be more clear to people who live here,” said Nicholas Bagley, a professor at the University of Michigan Law School, who has argued in a series of blog posts and in a New York Times op-ed that the policy would run afoul of civil rights laws. “It is a way of extending solicitude to people who live in the hard-bitten white rural counties,” he said, but not to black residents in poor urban neighborhoods.

Other states with work requirements that have already been approved could face similar challenges soon. The federal government’s approval letters have said that exceptions could be devised for economically troubled places.

But regions that have declined to invest in public transportation, or where policies have increased the costs of urban car ownership, have created the very definition of a structural barrier to employment.