The basic issue is that it is stupid to set DMV's up as immigration enforcement centers, and if you're not going to do that then it makes complete sense to give illegal immigrants drivers licenses.
I'm reminded of how Lou Dobbs blows a gasket every time he hears that an illegal immigrant might get a bank account. Why this is I have no idea. Getting a bank account isn't actually any different than getting a cup of coffee at a Starbucks. You're just contracting with a bank for a set of financial services they'll perform, including storing your money for you. It's an utterly mundane part of our economy. There's zero reason that whether their customers meet residency or citizenship requirements should be of any more concern to the bank than it should be to Starbucks. And given the fluid nature of immigration status it's even more absurd. One can open a bank account while, say, on a temporary student visa and still hold on to that account after the student visa expires and you leave the country. Given the wonders of international commerce and the internets, you can still access your bank account from abroad in various ways even if you haven't overstayed your visa.
