A new Tennessee law allows people who don't have a Social Security number to get a driver's license, meaning that illegal immigrants by the thousands have the opportunity to get state-issued identification.

Demand for licenses at some of the state's driver testing centers have already tripled, with lines winding out the door. 

And Tennessee is not alone. North Carolina and Utah have similar laws on the books. A handful of other states are considering it.

"We found it's more important to know that people who are in a car happen to know the rules of the road and can read the signs and pass a test, than it is why they are here and what they are doing while they are here," said state Sen. James Kyle, D-Memphis, the bill's sponsor.

But opponents say it doesn't make any sense to recognize people whose presence violates federal law. Critics are concerned that by issuing drivers licenses, states are giving illegal immigrants a false sense of legitimacy, and sending the message that  there are places within the U.S. they can call home.

"It's going to be even harder for employers to know that they're hiring illegal aliens if they're presenting legal driver's licenses," said Jack Martin of the Federation for American Immigration Reform.

Supporters insist the new laws are about safer roads, not immigration issues.

"What we're saying is they [illegal immigrants] live and work here... they are here... let's ensure that they know how to drive safely," said Dana Keeton of Tennessee's Department of Safety.

"They won't be driving illegally, but they'll be living illegally in the country. Not our issue ... We're worried about how they drive," she said.