He thumbed through the 70-page decision faster than any other human. This is the key, I think.
[Judge Simpson] thought it credible that state officials could get i.d.s into the hands of most voters who wanted them on election day. Many of the plaintiffs brought into the case to “put a face” on the case will have other means of voting, such as through absentee balloting. For those relatively few voters who will have significant difficulties getting voter id, and who cannot vote with an absentee ballot., they may well be entitled to an order, as applied to these voters only, barring the use of the id law as unconstitutional.
Simpson makes a couple of references to a weak state case, but he was convinced by their simple, effective tactic of proving that all 14 sob-story ACLU et al witnesses could find ways to vote. The most likely political response to this, I'd guess, will be a more-aggressive Democratic/NAACP/labor campaign to get absentee ballots in the hands of their trouble voters -- especially in places like Philadelphia -- and instruct these people on how to justify the need for the ballot. As John Fund likes to point out, even states like Pennsylvania, which require absentee voters to explain why they needed the extra time, do not double back and check whether they were telling the truth. There's literally never been a prosecution of lying to get an absentee ballot.