A friend of mine recently asked, rhetorically I presume, what could be the downside of requiring someone to show ID when voting?

A little bit of background for context: Over the past couple of years, the integrity of voting in Minnesota has been impugned by a parade of dubiously named organization, including Minnesota Majority and Minnesota Voting Alliance. These groups charge large-scale voter fraud on the part of a number of bogeymen, but more on that a bit later.

Minnesota has same-day registration, so you can register to vote at your polling station moments before you step into the booth. The claim that same-day registration requires a photo ID is not strictly true, but I suppose that is how 99% of people do it. Regardless, it is technically feasible, possibly with some unscrupulous help, to falsely register without a photo ID and vote in a precinct where you are not eligible to vote. This doesn’t seem to happen in practice. (How many rewards has Election Integrity Watch awarded, anyway?) Representative Steve Simon noted that of the 38 cases of voter fraud in 2008, all were due to felons casting a vote, felons who likely had with them their state-issued photo ID cards. And the RNC admitted that 2009 saw “no recent documented reports of voter fraud”.

Nevertheless, state lawmakers introduced Minnesota House File 210. Among other things, this bill requires the presentation of photo identification at polling stations in order to vote.

Now, I think my friend, the one who prompted this line of thought, is a great person. The wise citizens of Carver, Minnesota, recently elected him mayor, even while he struggled with the aftermath of being seriously injured by a drunk driver in the 11th hour of the campaign season. I also think his was a great question, even if asked rhetorically. It’s the kind of question that makes you think about why answers are rarely as simple as their questions.

My first reaction was to say that requiring a photo ID in order to vote amounts to a poll tax. This is a bit disingenuous, because an ID card is useful for more things than just voting. It’s more like a poll+ tax. The cost of a Minnesota ID card is $18.00. The cost of a driver’s license is a bit higher. How much of that fee you want to allocate to the “poll” part of “poll+” is up to you, but it’s probably not zero. If a requirement to vote is not a poll tax, it must be free—free as in free beer.

Okay, so let’s suppose we just make Minnesota State ID cards free. We must ensure that the requirements for obtaining an ID card are a superset of the requirements for registering to vote, which must be a superset of the requirements for voting. This seems straightforward, though there may be some subtle issues. For example, changing your surname when you get married does not invalidate your right to vote, but it may invalidate your current ID card. Since you cannot legally obtain an updated ID card until after the ceremony, the requirements for obtaining an ID card become more stringent than those for voting.

Okay, that’s a one-off. Let’s suppose we iron out those details to make the math work. Now what happens when you grow a beard? Or you change your hairstyle? Or you become the victim of a deranged man in a horrendous acid attack? Or you take a late-October vacation to Arizona and come back with a tan?

Or the election judge, for whatever reason, decides that your photo doesn’t look enough like you?

The potential has now been introduced for another form of electoral fraud: disenfranchisement. And this form of electoral fraud is likely to have a result that is much larger than inadvertently allowing 38 felons to vote (who would still be able to get away with voting anyway, since they are allowed ID cards).

Because I’m a geek, I see a lot of parallels between voting and statistical hypothesis testing. The vote is the controlled experiment. The null hypothesis is “a vote cast by citizen X is valid”. The alternative hypothesis is “a vote cast by citizen X is not valid”. Prohibiting a legal vote is a Type I error, and allowing an illegal vote is a Type II error.

Some forms of electoral fraud, such as gerrymandering, amount to intentional bias in the design of the controlled experiment. But other forms amount to either Type I errors or Type II errors. Intimidation and disenfranchisement are Type I errors, for example. Vote buying and ballot stuffing are Type II errors. I’m interested in the errors, here, because that is the debate. I’ll use disenfranchisement to epitomize Type I errors and ballot stuffing to epitomize Type II errors.

I see big differences between ballot stuffing and disenfranchisement:

• Ballot stuffing is expensive. Disenfranchisement is relatively cheap.
• Ballot stuffing is unambiguous. Disenfranchisement is easily argued against on the basis of interpretation.

As promised, let’s go back to Minnesota Majority and one of their favorite canards, that shady organizations drive suspicious buses of “voters” around to cast ballots in multiple precincts. How much would that cost?

• Charter bus on election day: $800
• Charter-bus driver on election day: $300
• Gas: $200
• Food for 40 homeless people you lured off the street: $200
• Brainwashing for 40 homeless people: free (comes with organization’s website)
• Administrative overhead: $300

Congratulations, you’ve just dropped $1800 for at most 40 votes in a few precincts, and you’ve left a mile-wide paper trail that spells out your nefarious intentions. Instead, you could have paid a few campaign staffers to canvas sympathetic neighborhoods the day before the election and gotten a better result. Or, you know, drive busloads of actual voters to the polls, because you probably don’t even need to feed them.

More permissive election law decreases the probability of disenfranchisement and increases the probability of ballot stuffing. More restrictive election law increases the probability of disenfranchisement and decreases the probability of ballot stuffing. The challenge is to find the right balance of election law.

Requiring photo ID to vote is an intuitive and appealing idea. I say that it is a wrong solution, not a bad solution. The integrity of our elections is important, and voter fraud (or election fraud of any kind) should be aggressively prosecuted. But the balance of election law should be biased against disenfranchisement. That is, election law should be more permissive than restrictive in order to reduce disenfranchisement.

Yes, this opens the door wider for ballot stuffing, but ballot stuffing is naturally curbed by its relative expense. Further, ballot stuffing tends to leave evidence that demonstrates the illegality without having to judge intentionality, which is something that can’t be so easily said of disenfranchisement. That is, ballot stuffing is also naturally curbed by the potentiality for criminal prosecution, a control that disenfranchisement largely lacks.

Photo ID voting is not about election integrity, because it will eliminate more legitimate votes than illegitimate votes; it is a net loss. Photo ID voting is about a collection of ideologically aligned organizations making a calculation that the elimination of votes will be a net gain only for candidates they support.