The Supreme Court’s decision upholding Indiana’s vote ID law was unable to secure 5 votes for a single rationale. Stevens, in an opinion joined by Kennedy and Roberts, rejected the facial challenge to the law but left open the possibility of future litigation if it was proven to be an undue burden. Scalia, in a concurrence joined by Thomas and reasonable, moderate Samuel Alito wanted to foreclose future litigation. (I assume Stevens may have joined the majority partly to keep Kennedy and Roberts on board with a more minimalist opinion.)
The key problem with the decision to uphold the statute is summed up in Souter’s dissent: “a State may not burden the right to vote merely by invoking abstract interests, be they legitimate, see ante, at 7–13, or even compelling, but must make a particular, factual showing that threats to its interests outweigh the particular impediments it has imposed. The State has made no such justification here, and as to some aspects of its law, it has hardly even tried.” Consider this remarkable passage from the Stevens opinion:
The only kind of voter fraud that SEA 483 addresses is in-person voter impersonation at polling places. The record contains no evidence of any such fraud actually occurring in Indiana at any time in its history. Moreover, petitioners argue that provisions of the Indiana Criminal Code punishing such conduct as a felony provide adequate protection against the risk that such conduct will occur in the future. It remains true, however, that flagrant examples of such fraud in other parts of the country have been documented throughout this Nation’s history by respected historians and journalists, that occasional examples have surfaced in recent years, and that Indiana’s own experience with fraudulent voting in the 2003 Democratic primary for East Chicago Mayor—though perpetrated using absentee ballots and not in-person fraud—demonstrate that not only is the risk of voter fraud real but that it could affect the outcome of a close election.
So the only type of fraud shown to have occurred in Indiana history is a type the statute specifically doesn’t address, and as it happens this apparently irrational choice happens to coincide with the partisan interests of the legislators who enacted the statute. This really isn’t good enough if you want to burden the fundamental right to vote.
The other thing to mention is that the “as-applied” challenge is problematic in the context of elections, because there generally isn’t a good remedy. It’s unlikely in the extreme that if the burdens imposed by the statute were decisive that the election would be run again. The better option would have been to strike the legislation and invite the legislature to craft legislation more closely tailored to its asserted interests.