Read the whole dissent from Judge Posner, but note this:

Stephen Ansolabehere & Nathaniel Persily, “Vote Fraud in the Eye of the  Beholder: The Role of Public Opinion in the Challenge to Voter Identification Requirements, 121 Harv. L. Rev. 1727 (2008), finds that perceptions of voter impersonation  fraud are unrelated to the strictness of a state’s voter id law. This suggests that these laws do not reduce such fraud, for if they did one would expect perceptions of its prevalence to change. The study also undermines the suggestion in the panel’s opinion (offered without supporting evidence) that requiring a photo ID in order to be allowed to vote increases voter confidence in the honesty of the election and thus increases turnout. If perceptions of the prevalence of voter impersonation fraud are unaffected by the strictness of a stat’e photo ID laws, neither will confidence in the honesty of elections rise, for it would rise only if voters were persuaded that such laws reduce the incidence of such fraud.

The panel opinion dismisses the Ansolabehere and Persily article on grounds it was published in the Harvard Law Review, it was not peer reviewed. So much for law reviews. (And what about Supreme Court opinions? They are not peer reviewed either. Persily, incidentally was chosen to be research director of [the non-partisan Bauer Ginsberg commission].