There are three inducements of support that Americans are powerless against: the promise of whiter teeth, the suggestion of no-diet weight loss and the cause of justice.

Political campaigns tend to couch their appeals in terms of the last, though parts of the Romney-Ryan economic pitch could be described as the second. In today's truly divisive debates, both parties have usually engineered a rhetorical claim to the side of fairness: gay rights advocates propelled themselves forward when they began to argue for "marriage equality" against the outdated complaint of "special rights".

Americans rankle at unearned privileges as much as they rally, in the main, to equality. Hence the widespread, enthusiastic support of voter ID laws (they poll with about 75% in favor) makes total sense if you see the laws exactly the way their authors and promoters talk about them – as barriers to voter fraud. After all, voter fraud is when criminals unfairly manipulate voting, the most basic expression of fairness available in a democracy.

Asking Americans if they support measures against voter fraud is like asking if they support measures against adults suiting up for Little League baseball. The problem is that there are probably more cheaters in baseball than voting: a recent analysis found cases of alleged voter fraud running about one for every 16,000 voters. What's more, voter ID laws work in such a way that a no-adults-in-Little-League equivalent would ban not just grownups from playing, but also anyone who looked adult-ish and didn't show up for practice with documentary evidence of minor status.

The metaphor breaks down pretty quickly, however, and not just because a tall-person-free Little League might wind up still being a decent pastime for those involved (the tall people could play elsewhere). In real-life democracy, there is no farm team. You either get to play or you don't. What's more – as American as playing baseball is – it's not a legal right.

The pre-eminence of voting as a right, and not a privilege, is where the facile arguments that make voter ID laws sound so commonsensical falter as well:

"You have to show a picture ID to buy Sudafed … you have to show a picture ID to set foot on an airplane."

So went South Carolina Governor Nikki Haley's argument at the Republican convention. So why not to vote? Somehow, this is not a line of reasoning conservatives favor when it comes to buying a gun, but no matter! Let's agree that the risks of someone with bad intentions buying Sudafed, or getting on a plane are bad enough that it makes sense to err on the side of caution. The ID-less people who want to buy Sudafed just to treat a head cold, or who are badly organized travelers, do not suffer overmuch – and have other options.

By contrast, those with good intentions and blameless records who are barred from legally casting a ballot because they lack ID are not just being inconvenienced; they are being denied the right that defines democracy. Voting is so important to democracy's functioning as an equalizing force that it is the first thing those in power deny the minority and the last thing they grant. Campaigns for voter ID laws may have multiplied dramatically in recent years, but they are far from new. They are simply an innovation in a decades-long campaign to deny those at the margins – blacks, the poor, the disabled – the right to representation.

As Republicans' economic agenda pushes us further toward a winner-take-all society, their state-level legislative voter ID agenda shows an impulse to eliminate other players entirely.

As personal and private as voting is, the forces at work to deny the franchise have been subsumed by larger, technocratic forces. The biggest threat to voting rights posed by activists such as "True the Vote" – a conservative outfit claiming to ferret out voter fraud – is not intimidation at the polls or requiring voter ID: it's computer-driven, human-assisted purges of voter rolls, often brought about by private citizens "alerting" local governments to possible fraud, but also instigated by Republican officials.

Called "caging", this technique often relies on using returned mail as proof that the voter has registered illegally (under a false address) – no matter if the voter has moved but retains residency in the state. This method produces very favorable results in areas with high foreclosure rates, like … well, everywhere, really. The best-known example of caging is from 2000 in Florida, with an attempt to clear the voter rolls of felons using a computerized list that wound up striking 12,000 eligible citizens.

There are no witnesses to these purges, no ugly footage to brandish on the evening news. What's more, there is not an equal and opposing force: no computer program that can create a list of people who should be allowed to vote. The Common Cause/Demos paper last week that spurred some the current coverage of voter ID makes suggestions for leveling the playing field, such as making challenges to voter registration as individuated as possible (requiring a signed affidavit for each challenge, for instance).

In the end, though, once challenged, the only way for a would-be voter to push back is by a literal act of personal integrity: showing up at the county registrar's office or hearing, usually. While I can imagine the satisfaction of telling a conservative activist who has challenged my rights to "say that to my face", the fact is that if someone has been challenged because he or she has no driver's license or is struggling with permanent housing, they may not even find out they've been challenged.

Many of the arguments for voter ID laws and other anti-fraud measures make sense in the abstract: yes, voter fraud is bad! But nothing about voting is abstract. It is an inherently physical act; it is about what country one chooses to call home. In theoretical terms, psychologists still puzzle over why people vote at all. It would be more logical, more immediately self-serving to not vote. Voting takes time and effort and, in the grand scheme of things, one vote doesn't matter. Unless it's yours.

Ultimately, people vote so that they can continue to do so.