The argument against is that issuing driver's licenses to illegals opens the door to more and more privileges rightly reserved for citizens. One is voting. The Motor-Voter law of 1993, by tying voter registration to the issuing of driver's licenses, allows illegals to vote. Many illegals vote now. With driver's licenses, they may do so in very large numbers.
More broadly, the driver's license is nearly fatal to the fading distinction between legals and illegals. It is the closest thing we have to a national ID card, and it opens a great many doors closed to illegals. It establishes identity for benefit eligibility, employment and credit. Since many people who enter this country illegally have no way to prove who they are, giving them driver's licenses magnifies security problems. An undercover officer and fraud expert told Fox News, "In California, you can now obtain a gun, explosives, jobs in secure areas -- even at the nuclear power plant -- with a driver's license."
Another gain for illegals is the campaign to allow them to attend state universities at the in-state resident rate. Allies of the illegals have drummed up a lot of sympathy for students who are illegals and even more sympathy for the children of illegals who were no part of their parents' decision to come here. But these steeply discounted rates were clearly intended for legal residents. It's wrong to give the cheap rate to someone who has no right to be here, while an out-of-state U.S. citizen may have to pay four to 10 times as much.
Compassion-driven policies have a cost. While the United States is spending millions to control illegal immigration, many states and localities are working, in effect, to undermine immigration law and to make illegal immigration more attractive and therefore more common. It makes no sense.