While I agree with the spirit of the [ACLU] case — and indeed we don't have debtors prison in this country — one has to wonder about what this may lead to.
Sure you have fulfilled your sentence, oh wait — except for that restitution. So in effect you haven't completed paying (literally) for your crime. So now would it be more prudent for the judge to put you back into jail for contempt after not paying for a year?
Probably not. But look at the case of someone who isn't paying child support. Since people are often never jailed for non-payment but still in contempt, the ACLU's statement doesn't apply: “Denying voting rights to those who have served their time based solely on their inability to pay a particular debt amounts to unconstitutional discrimination.”
Personally, I think that once someone has not paid child support for several months, a good wake up call would be to spend a few hours in jail, just a holding cell. That would probably shock most people and spur them to action.