Justin Levitt, an associate professor of law at Loyola Law School (L.A.) has a disturbing post, “The Danger of Voter Fraud Vigilantes” up at The New York Times. Leavitt provides examples of overzealous voter vigilantes, most notably in Montana, where six thousand citizens had their voting rights compromised by self-appointed “amateur detectives” and then explains:

…In the final days before the election on Nov. 6, “voter integrity” groups have begun to object to the participation of voters they find suspicious. Civic participation in our electoral process is not only welcome, but necessary. But excess zeal and an absence of accuracy turns volunteers into vigilantes.
The past weeks have seen challenges based on ostensible felony status in Florida, ostensible deaths in North Carolina and ostensible address problems in Ohio, among others. Some of these challenges appear to be the work of isolated individuals, others are coordinated by local groups “empowered by” national entities like True the Vote. The common thread is that the challenges are based not on personal information about particular voters, but computerized scans of data records.
Thus far, most local election officials have met the challenges with firm resistance. These officials understand that they must safeguard the voting rights of their legitimate constituents, and, backed by federal law, they are admirably standing their ground against the tide. By and large, they have assessed mass challenge efforts with a skeptical eye.
Their skepticism is appropriate. One need not impugn the partisan, racial or tactical motives of those sponsoring mass challenges to fear their impact. I suspect that most citizens who have signed up for such efforts honestly (and commendably) believe that they are valiantly protecting the franchise against the elusive scourge of voter fraud. But enthusiasm without precision causes real problems.

Levitt may be over-trusting with that last observation. But he is right on target in defining the responsibility election officials have toward such voter vigilante exercises:

Maintaining the voter rolls is a delicate science. Officials need to keep records clean, but they also need to ensure that voters are actually ineligible before jeopardizing their constitutional rights. Taking lapsed records and ineligible people off of the rolls helps prevent potential problems; taking eligible individuals off the rolls immediately creates real ones. The proper balance calls for the care of a skilled surgeon, excising cysts from the rolls in an atmosphere of quiet calm. Take out the bad, but be careful not to cut out the good. Mass computerized challenges in the closing days of an election cycle are like operating with a chainsaw. The results are unhealthy, no matter how good the operator’s intentions.

Levitt cites an extensive litany of common mistakes and things that can go wrong in the voter certification process. He warns that “At the polls, an eligible voter’s ballot cannot turn on the outcome of a shouting match built on the flawed product of a flawed computer algorithm. Citizens walking around with long lists of ostensibly illegal voters are most likely walking around with long lists of mistakes.” Sadly, in 2012, it appears that too many of these overzealous voter vigilantes are targeting Democrats.