George W. Bush visited an abstinence education program in South Carolina the other day and endorsed the concept on the spot. It turns out, he is a long-standing proponent of sexual abstinence and has challenged Texas youth to remain virginal until they are in a "biblical marriage relationship." If Bush means ordinary marriage, he is talking about a median age of 26. You can readily see why this man would make a great president. He has figured out a way to drive down the age of marriage.

American politicians will say remarkable things, and it is accepted that from the first day of a political campaign to the last, a candidate can leave his brains at home. But Bush, exhibiting the keenness of mind that has so awed his fellow GOP governors, has outdone your average politician. Here is a man renowned for being a cut-up and roue as a young man telling other young men they should spend much of the day in a cold shower. Not since Saint Augustine, who himself had quite a youth, has there been such a conversion.

Except that Garry Wills instructs us in his engrossing new book on the Bishop of Hippo that Augustine was not the libertine he was supposed to have been. Bush, though, apparently was -- and all he will say on the subject is that when he was young and irresponsible, he was young and irresponsible. I like that. We all are entitled to our youths and, even, to a personal life. Bush will get no questions from me on this score.

So I won't ask what he did when he was young, but merely how he has forgotten what it was like to be young. The young are not merely old people who happened to be born later. They are different. They think differently. They are designed by nature to do -- to quote Irving Berlin -- "what comes natur'lly." Sex is one of those things. It is best to plan for that contingency. To think otherwise ignores reality.

Don't get me wrong. I have nothing against abstinence. But there is a finger-wagging either/or tone to what Bush says. To suggest abstinence as a substitute for sex education is truly the victory of hope over experience. In the first place, no proof exists that abstinence programs work. They might in the short run but not over any length of time. Kids will be kids, and when they start to kid around it is best for all concerned that they don't accidentally produce even more kids. I'm talking safe sex. I'm talking contraception.

Apparently, Bush does not rule out sex education. But he talks about it in a disparaging fashion, asserting that it sends a "contradictory message" to kids. If given a choice, he no doubt would choose one and not the other -- abstinence-ed over sex-ed.

The practicality of this position -- not to mention its sincerity -- eludes me. It treats sex as shameful, sinful. Kids won't talk about it, but they will surely do it -- and not, of course, in a mature, safe way. The United States pays a steep price for its sex-is-shameful attitude. An openness about sexual matters gives Western Europe a birthrate for teenage women that no celibacy program here could hope to attain -- nine out of 1,000 in France, for instance, seven out of 1,000 in the even more liberated Netherlands. In the United States, the figure is 54.7 out of 1,000.

It just so happens that I don't think 14-year-olds should have sex. I'm less sure of 16- and 17-year-olds, and after that it depends on the person. Mature, responsible people are entitled to an erotic life. It is preposterous to suggest that it should be saved until marriage, especially when marriage itself is being postponed -- college, graduate school, etc. There is a dusty, prudish quality to Bush's message, as if sex is no fun at all but part of the heavy obligations of marriage -- like waterproofing the basement or buying life insurance. There's nothing wrong with responsible sex. There's plenty wrong with the irresponsible kind.

Bush's position is sheer hypocrisy -- either that or a sincere statement of blinding impracticality. It is a minor thing, I suppose, and no reason by itself to reject the man or his candidacy. But it suggests a mushy mind, a man in the thrall of faith-based absurdity who has learned little from his own life. Being young and irresponsible is forgivable. Being old and irresponsible is something else again.