Chief Judge Theodore A. McKee seemed concerned, however, that Hazleton could extend laws to more than landlords and employers: "What about selling food to any customer who may be in undocumented status? What about public restrooms? How far do we go?"
McKee and Judges Richard L. Nygaard and Thomas I. Vanaskie held the appeal for further study and did not say when they might rule.
Hazleton's laws never took effect; a federal judge invalidated them after challenges by the American Civil Liberties Union's Immigrants' Right Project and Latino advocates.
The Third Circuit court affirmed that decision in 2010. But in May 2011, the U.S. Supreme Court affirmed an Arizona business-licensing law for employers who hire illegal immigrants. This June, the high court, ruling in another Arizona case, invalidated most of a package of tough border-control laws.
Despite the federal government's primacy in controlling immigration, Kobach argued that nothing in the Supreme Court's Arizona decisions prevents municipalities from passing laws that support or mirror federal policy.
ACLU lawyer Omar C. Jadwat urged the Third Circuit court to reaffirm its decision invalidating Hazleton's laws.
Jadwat said Kobach was misreading the Supreme Court's Arizona decisions.
"Hazleton is taking on and undermining federal authority to exclusively make these decisions," Jadwat said.
Hazleton officials enacted the laws in 2006 at a time when new Latino residents had swelled its population about 9 percent, to 25,000.
The ordinances empowered the city to fine landlords who knowingly rented to illegal immigrants and to threaten the business licenses of employers who hired them. Once told by Hazleton of a suspected illegal immigrant, the business would have three days to fire the worker or confirm the worker's legal status.
Hazleton was one of many communities to move against illegal immigrants. The same year officials in Riverside, Burlington County, passed similar laws in reaction to a burgeoning community of Brazilian immigrants. The law triggered an exodus, and Riverside revoked the laws a year later.
Contact Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org, or @joeslobo on Twitter.