The logic behind laws requiring voters to provide a government-issued photo identification card is simple and seductive: If you need to show an ID to board a plane, open a bank account, get public aid or do any number of other things, it only makes sense to do the same before casting a ballot.

That was what Wisconsin Gov. Scott Walker, a Republican, said in 2011 as he signed a law imposing this new mandate. “There really is no barrier for people,” he asserted. “Particularly in a society where people need photo identification for just about everything else, including checking out a book from the library … it’s a reasonable requirement.”