The Wall Street Journal reported this week that the Transportation Security Administration is testing sophisticated machines that use elaborate algorithms to determine whether air travelers have "hostile intent." The machines measure your sweat output, pulse rate and other tells while asking questions such as: "Are you planning to immigrate illegally?" "Are you smuggling drugs?" "Do these stupid questions make you feel like committing a terrorist act?"

OK, I made the last one up, and I shouldn't make fun because supposedly the Israelis have figured out how to make this stuff work. The thinking behind this program rests on the assumption that searching for every kind of potential weapon or explosive is too reactive. Find the bad motives, and the rest will follow.

If it works, great. But one of the frustrating reasons the U.S. government feels compelled to spend all of this time and energy coming up with computerized lie detectors is that civil libertarians can't trust airport security personnel to do the same thing. Why? Because it's possible for humans to be racist.

The TSA's more established security system, Screening Passengers by Observation Technique, or SPOT, relies on human intelligence instead of the artificial kind. Teams are trained to scrutinize passengers for more than 30 questionable behaviors, according to the Journal: "They look for obvious things like someone wearing a heavy coat on a hot day, but also for subtle signs like vocal timbre, gestures and tiny facial movements that indicate someone is trying to disguise an emotion."

This apparently is unacceptable for civil libertarians.

"Our concern is that giving TSA screeners this kind of responsibility and discretion can result in their making decisions not based on solid criteria but on impermissible characteristics such as race," the ACLU's Gregory T. Nojeim told the Journal.

In other words, while our enemies are coming up with ingenious ways to murder Americans, we're coming up with ingenious ways to search for our enemies in the nicest manner possible. No amount of training, it seems, can immunize against the real threat to America: the possibility that somewhere, at some time, a TSA cop might pull an Arab or South Asian out of a line at an airport unfairly and talk to them for five minutes.

Note: We're not talking about training security personnel to racially profile passengers. Quite the opposite. The ACLU's problem is with training officers not to racially profile if that training nonetheless gives them enough autonomy so that it's theoretically possible to take race into account.

What is so infuriating about this is that the ACLU favors policies which discriminate against all sorts of people - old people, women, children and others who, under random searches and other idiotic numerical formulas, are pulled aside for literally no reason at all.

All of this is happening against a backdrop of a war on terror in which roughly 99 percent of jihadi terrorists are of either Middle Eastern or South Asian descent and 100 percent of them are Muslim.

Critics of racial profiling say that it wouldn't have stopped Richard Reid (the shoe bomber) or Timothy McVeigh (the Oklahoma City bomber). This is a red herring. Nobody ever proposed that race should be the only factor, or even the most important factor. But why can't it be one of those 30-plus factors? The Brits who foiled this most recent plot were allowed to take race into account. Was that too high a price to pay for thwarting mass murder?

The terrorists we're looking for are overwhelmingly young, male Muslims from places like Pakistan and Saudi Arabia. Why is it morally superior to inconvenience old Mormon women of Swedish descent - for no reason at all - as much as young men from Pakistan?

Two alleged members of the British liquid explosives plot were young men of British descent who converted to Islam, and one was a woman with a child. Only a fool would advocate a system that, as a rule, deliberately excludes such people from scrutiny. But isn't it equally foolish to spend vast sums on machines designed to interpret the facial twitches and sweat glands of millions of passengers out of an irrational phobia of racial profiling?

Ron Suskind's new book, "The One Percent Doctrine," explores Dick Cheney's view that if there's a 1 percent chance terrorists might detonate a nuclear bomb in an American city, the government must act as if there's a 100 percent chance. Despite the guffawing this elicited from administration critics, it strikes me as eminently sensible. (If there were a 1 percent chance the snake in your back yard would kill your child, wouldn't 1 percent equal 100 percent for you, too?) The ACLU's self-indulgent position, meanwhile, seems to be that if there's a 1 percent chance a cop will be a racist, we must act as if it's a 100 percent chance. And that means humans can't ever be trusted.