Reductio ad Absurdum arguments are among my favorites. They are a sort of refutation by contradiction. Goose and gander. If I make an argument and an opponent applies the same logic in a different direction, getting a result with which I disagree, I may be caught in a contradiction. The rhetorical technique is legitimate. It has been applied throughout history.

In 1870, states that had been part of the Old Confederacy were faced with a problem. Freed slaves were allowed to vote. The federal government had been run by those with such radical ideas as voting rights. In fact, Thaddeus Stevens and others had become known as Radical Republicans. So a few counter measures were taken.

Poll taxes were imposed. Some objected, but the reductio argument by proponents was simple. We charge for other licenses, don't we? Isn't voting just as important, just as much a privilege? If we were to object to poll taxes, why not object to all taxes?

Literacy tests were also imposed. The tests required intimate knowledge of the Constitution and the amendments. Those who had voted in previous elections, or whose grandfathers had voted, were exempted. The term "grandfathering in" comes from that practice. By some coincidence, that left mostly black people and poor folks to take the tests.

Testing offices were moved and assigned highly restricted hours. This tended to keep working people from leaving their jobs to take tests.

In 1964, nearly a hundred years later, the federal government, temporarily in the charge of liberals, abolished literacy tests. The reductio argument in favor of the tests was simple. We required testing for all sort of licenses, including licenses to drive. Wasn't it just as important to safeguard the right to vote from those unqualified? If we abolish literacy tests for voting, we should abolish tests for drivers licenses as well, right?

And today, a number of states in Republican control are passing laws requiring special photo IDs in order to vote. Those already with a license to drive are exempted, an interesting form of grandfathering. Drivers are said to already possess a valid voting pass. By some coincidence, this leaves mostly black people, poor folks, and retirees, who are required travel about getting documentation, then the photo IDs themselves. Those travelers happen to be mostly Democratic voters. Issuing offices are often moved and assigned highly restricted hours. Employees are forbidden from giving directions. Those who disobey, and provide information, are fired. Such conveniences as chairs for the elderly are removed during long waits. All this tends to keep those who rely on public transportation from making additional trips. As many as 5 million legitimate voters are targeted, being kept from voting.

The reductio as adsurdum argument is made here as well. "Why should we stop at opposing a picture ID for voting? I say we should oppose showing an ID for anything, including buying liquor, driving, staying at a hotel, boarding an airplane... everything!"

A spokesperson for Governor Rick Perry transmuted the reductio argument into an affirmative defense.

By applying to voting the same standard that is commonly applied in cashing a check or applying for a library card, Voter ID can ensure an accurate reflection of the will of the voters.

One counter to the reductio ad absurdum argument is to show a substantial difference between cases. You can't very well show that the same logic produces a bad result if the case doesn't really apply. So just show the difference.

For example, we could point out that the current voting ID system in place in pretty much every jurisdiction works pretty well. We could point to the fact that the incentive for voter fraud is low, the penalty is high, and the odds of being caught are substantial. We can show a substantial amount of research that has been unable to discover the type of voter fraud that a photo ID can affect.

These facts are not true with library cards, where penalties are low and book theft actually does happen. Even at that, photo IDs are not required for library cards in most jurisdictions. Cashing a fraudulent check involves a more substantial gain for those able to pull it off. Boarding an airline involves a substantial danger in those cases in which security precautions are not taken. Liquor is not sold to minors for coherent reasons, and not everyone is carded. Driving is held to be a privilege reserved for sober responsible adults. This is because the incentive to drive without a license is substantial enough, and the result can be deadly enough, to present a reasonable need.

For proponents of restrictive voting requirements, the fact that it keeps people from voting seems less of a bug than a feature. The same sorts of restrictive office hours as happened many decades ago, closed locations, and denied information, are a vivid reminder of days we thought we would never see again.

Occasionally, we'll find a strictly-split-the-difference sort of observer who regards such tactics as a normal level of simple partisanship. Fiddling around with basic rights strikes me as substantially more than that.

"As we all know," sneers a sarcastic correspondent, "requiring a photo ID for anything is prima facia evidence of racism. We can't tolerate this racism, which is obviously what conservatives want."

Well, no. The additional restriction is motivated by a simple desire to win. The racism is incidental.