A new measure in small-town Lukeville, Ariz. requires students to prove their citizenship before they can ride the school bus.

Less than 500 students go to Ajo Public Schools, but some of them come from a zone between Lukeville and the Mexican border where there's no school district at all.

"It is the area from Ajo to the international border," said Dr. Robert Dooley, schools superintendent. "It's unorganized territory. There's no school district there."

It has been hard to find out who's a legal citizen and who's not.

Dooley said all children riding on district buses must prove they deserve the right to an education that comes with being an Arizona resident.

"We want an electric bill or water bill, or we could also accept a land-line telephone bill," Dooley said.

"As long as it actually shows a physical location, a physical address in Lukeville, then we'll take that as proof that they actually live in Lukeville," said Ricardo Hernandez, Pima Country Schools chief financial officer.

Some realize Arizona's newly strict attitude puts somewhat of a strain on race relations in the border town.

"It's always unfortunate when there are certain politics injected into how we educate kids in the state," Hernandez said.

Some parents sympathize with the children who may not be in the country legally.

"Everybody always says they don't want nobody to be left behind," Ajo parent Margot Alegra. "I don't think it would hurt for them to get an education here."

However, many Arizonans are tired of footing the bill for illegals in the state, including the $6,000 a year it takes to educate a non-resident in the public schools.

"I pay taxes for my kids to go to school," parent Bobbie Sharp said.  

Sharp supports the notion that all children attending the district's schools should prove they're a U.S. citizen.

"Everybody should do that," he said.