The Justice Department’s lawsuit against South Carolina has rekindled political war over state voter identification laws. While the merits of the suit will surely be hashed out in the political arena, the Supreme Court has in fact weighed in on the constitutional arguments offered by opponents of voter ID laws, and found them wanting.

In light of the issue’s prevalence, it’s worth revisiting that decision to see what the nation’s highest court had to say about voter ID laws.

Opponents of those laws usually make a pair of arguments against them: they claim the laws impose overly burdensome restrictions on voting, and that they are a solution in search of a problem, given the relatively low incidence of voter fraud. Neither of those arguments stands up to the Supreme Court’s thorough examination of the issue.

In the 2008 case Crawford v. Marion County Election Board, the court upheld an Indiana voter ID law, which the National Conference of State Legislatures classifies as one of the strictest in the nation. The law requires voters to present a photo ID at polling places. Those who can’t may cast a provisional ballot, which will only be counted if the voter affirms the ballot in person – with a photo ID – within 10 days.

The Supreme Court upheld a decision by the Seventh Circuit Court of Appeals, finding that “showing a free photo identification is not a significant increase over the usual voting burdens, and the State’s stated interests are sufficient to sustain that minimal burden.” It’s also worth noting that prior to enacting the voter ID law, Indiana did charge for photo IDs. A provision in the law repealed that fee, presumably to rescind financial barriers to voting. Like Indiana, South Carolina offers free IDs to state residents.

The majority opinion, written by then-Justice John Paul Stevens – no conservative stalwart – examined each of the objections offered to this day in opposition to voter ID laws. Let us review each in turn.

Claim: Voter ID laws are excessively and prohibitively burdensome

Indiana provides a free identification card to any resident who requests one from the state’s Bureau of Motor Vehicles. Traveling to the BMV and requesting one, therefore, is the extent of the restrictions on voting.

Even voters who show up to the polls on election day without an ID, as mentioned above, can cast a provisional ballot, which will be counted as long as the voter visits the election board within 10 days of the election, and produces a photo ID or a valid objection to having one (indigence or religious belief).

The free IDs and provisional ballots mitigate any excessively burdensome voting restrictions, the court ruled. Voters who simply do not have an ID can easily obtain one: “the inconvenience of making a trip to the BMV, gathering the required documents, and posing for a photograph,” Stevens wrote, “surely does not qualify as a substantial burden on the right to vote, or even represent a significant increase over the usual burdens of voting.”

For certain classes of voters, however, those requirements may provide additional burdens. Those include the homeless, indigent, or elderly, and those with religious objections to being photographed. The law’s inclusion of provisional ballot exceptions, the court ruled, are ample to mitigate those restrictions. “And even assuming that the burden may not be justified as to a few voters,” Stevens added, “that conclusion is by no means sufficient to establish petitioners’ right to the relief they seek in this litigation” – namely, invalidation of the entire law.

Key to the court’s decision was the fact that the petitioners had not disputed the state’s interest in protecting the integrity of the voting process. Rather, they claimed that the law was a partisan attempt to restrict voters, to the advantage of state Republicans.

But “while the most effective method of preventing election fraud may well be debatable,” the court ruled, “the propriety of doing so is perfectly clear.” If the impetus for the law were partisan in nature – i.e., were unrelated to the electoral process – even the minimal burdens placed on voters would render the law indefensible. But the law was spurred by a legitimate concern – one that even its opponents could not dispute – and “the ‘precise interests’ advanced by the State are therefore sufficient to defeat petitioners’ facial challenge,” the court found.

Claim: Voter ID laws are unnecessary due to the relatively low incidence of voter fraud

The actual incidence of voter fraud in Indiana was only tangentially relevant to the validity of the law, the court ruled. While no evidence of fraud was included in the record by the respondents, “flagrant examples of such fraud in other parts of the country have been documented throughout this Nation’s history by respected historians and journalists,” including examples in Indiana itself.

It was therefore unnecessary for Indiana to show that the law responded to documented cases of voter fraud that it would attempt to prevent or penalize. The very real possibility that fraud could occur – demonstrated by the fact that it had occurred elsewhere – was sufficient rationale for the law.

A corollary to this line of objections from voter ID opponents is that the documented voter fraud cited by the laws’ proponents would not actually be prevented by a photo ID requirement – absentee ballot voting, for instance. But the court ruled that a 2003 instance of absentee ballot fraud in Indiana demonstrated that voter fraud of any kind “could affect the outcome of a close election,” and therefore supported the state’s case for the law.

Also worthy of consideration, the court noted, is the state’s real interest in protecting the perception of fair elections and voter faith in the integrity of state elections. “Public confidence in the integrity of the electoral process has independent significance,” the court ruled, “because it encourages citizen participation in the democratic process.”

That passage is key, since it establishes a rationale for voter ID laws that does not require that fraud be widespread. Efforts to avoid the perception of fraud or the belief that it could take place – both of which could discourage citizens from voting – are sufficient to merit the voter ID requirement.