Immigrant Laws Tread Uncharted Legal Path

But Munley rejected the provision on several grounds, calling the loss of a license the "ultimate sanction" because it would force employers out of business. Congress, he wrote, would not have drawn up such intricate federal employment regulations had it meant to allow states this kind of opening.

Law enforcement is another gray area. Congress allows state and local authorities to make arrests under some criminal immigration laws and enter into agreements with federal authorities to enforce immigration law more broadly, experts said. But federal appeals courts have offered varying interpretations of how far those powers go and whether they extend to the enforcement of civil violations, such as overstaying a visa.

Those judgments mean little for Virginia and Maryland, whose 4th Circuit appeals court has not weighed in, experts said.

Prince William and Loudoun counties have passed resolutions designed to limit illegal immigrants' access to public benefits. Although illegal immigrants are entitled to schooling from kindergarten through 12th grade, immunizations and emergency medical treatment, the federal Welfare Act denies them most other assistance, including public housing, disability benefits or "any similar benefit to which payment or assistance is provided."

The line is fuzzier when it comes to locally funded benefits. What about, say, checkout privileges at public libraries?

"It wouldn't shock me if a court were to say this is a reasonable, measured response," said Washington University law professor Stephen Legomsky. "On the other hand, a court is just as likely to say that the states have no business distinguishing those of its residents who have broken federal immigration laws and its other residents."

For some local lawmakers, it adds up to a conundrum.

The ambiguity was on public display in Richmond last month, when Virginia's illegal-immigration task force -- a new panel of state lawmakers, community leaders and law enforcement officials -- sat through a crash course on what federal law allows states to do about the issue. With each PowerPoint slide, the members' brows grew more furrowed.

Several recent immigrant-related bills would have been void if the General Assembly had passed them, explained their two instructors, lawyers from a Richmond firm and the state attorney general's office. In fact, one Virginia law on the books since 1977 -- making employment of illegal immigrants a misdemeanor -- has no teeth.

Did state authorities have the right, lawmakers asked, to enforce criminal immigration laws? The lawyers were not sure. Could they yank business licenses from the employers of illegal immigrants? Probably, one said. But not without a challenge, the other added.

As the Virginia task force's co-chairman, Del. David B. Albo (R-Fairfax), put it: "I've been working on this for three years, and everybody is confused about what you can and can't do. . . . You ask four attorneys, and you'll get four answers."

Albo, himself a lawyer, asked whether state police could arrest people who approached them and said they had expired visas. Probably not, the lawyers said, because that is a civil immigration violation. And if the person said he had entered the country illegally? Probably so, he was told, because that is a criminal violation.