I have moved across state lines several times, and as long as I had a still-valid license from my old state, I had no problems getting a new license with only that as ID. Methinks BOTH had expired licenses, in which case their problem isn't just voting, but driving legally. Plus, every state requires you to get a new, valid license within a month or two of moving there, which these two clearly did not.
So the moral is, if they had simply followed the law for getting a new state driver's licenses after moving there, they would have no issue now having ID to vote. But somehow this new regulation is too onerous to follow, and their clearly contrived effort to make this seem difficult is just a setup for a lawsuit.
A. Some legal document that shows your written signature.One document can satisfy more than one category. Anything you use, though, has to be current, not expired. There are very few people who cannot manage to get a state ID. There is almost always a way if they actually live here and aren't in the U.S. illegally.
B. Some legal document that shows date of birth (current IL state ID or driver's license, a U.S. passport, a birth certificate, USCIS forms, etc)
C. Social Security number.
D. Proof of residency (2 documents required, such as homeowner's insurance policy, a utilities bill in your name, medical claim or statement of benefits, credit report, deed, title, etc).