Maybe, at least in theory, the full understanding and application of our regulative principle is turning out to be not so exotic and untenable after all . . . .

Devamrita Swami

The English writer Daniel Defoe is best remembered today for creating the ultimate escapist fantasy, "Robinson Crusoe," but in 1727 he sent the British public into a scandalous fit with the publication of a nonfiction work called "Conjugal Lewdness: or, Matrimonial Whoredom." After apparently being asked to tone down the title for a subsequent edition, Defoe came up with a new one - "A Treatise Concerning the Use and Abuse of the Marriage Bed" - that only put a finer point on things. The book wasn't a tease, however. It was a moralizing lecture. After the wanton years that followed the restoration of the monarchy, a time when both theaters and brothels multiplied, social conservatism rooted itself in the English bosom. Self-appointed Christian morality police roamed the land, bent on restricting not only homosexuality and prostitution but also what went on between husbands and wives.

It was this latter subject that Defoe chose to address. The sex act and sexual desire should not be separated from reproduction, he and others warned, else "a man may, in effect, make a whore of his own wife." To highlight one type of then-current wickedness, Defoe gives a scene in which a young woman who is about to marry asks a friend for some "recipes." "Why, you little Devil, you would not take Physick to kill the child?" the friend asks as she catches her drift. "No," the young woman answers, "but there may be Things to prevent Conception; an't there?" The friend is scandalized and argues that the two amount to the same thing, but the bride to be dismisses her: "I cannot understand your Niceties; I would not be with Child, that's all; there's no harm in that, I hope." One prime objective of England's Christian warriors in the 1720's was to stamp out what Defoe called "the diabolical practice of attempting to prevent childbearing by physical preparations."

The wheels of history have a tendency to roll back over the same ground. For the past 33 years - since, as they see it, the wanton era of the 1960's culminated in the Supreme Court's Roe v. Wade decision in 1973 - American social conservatives have been on an unyielding campaign against abortion. But recently, as the conservative tide has continued to swell, this campaign has taken on a broader scope. Its true beginning point may not be Roe but Griswold v. Connecticut, the 1965 case that had the effect of legalizing contraception. "We see a direct connection between the practice of contraception and the practice of abortion," says Judie Brown, president of the American Life League, an organization that has battled abortion for 27 years but that, like others, now has a larger mission. "The mind-set that invites a couple to use contraception is an antichild mind-set," she told me. "So when a baby is conceived accidentally, the couple already have this negative attitude toward the child. Therefore seeking an abortion is a natural outcome. We oppose all forms of contraception."

The American Life League is a lay Catholic organization, and for years - especially since Pope Paul VI's "Humanae Vitae" encyclical of 1968 forbade "any action which either before, at the moment of or after sexual intercourse, is specifically intended to prevent procreation" - being anti-contraception was largely a Catholic thing. Protestants and other non-Catholics tended to look on curiously as they took part in the general societywide acceptance of various forms of birth control. But no longer. Organizations like the Christian Medical and Dental Associations, which inject a mixture of religion and medicine into the social sphere, operate from a broadly Christian perspective that includes opposition to some forms of birth control. Edward R. Martin Jr., a lawyer for the public-interest law firm Americans United for Life, whose work includes seeking to restrict abortion at the state level and representing pharmacists who have refused to prescribe emergency contraception, told me: "We see contraception and abortion as part of a mind-set that's worrisome in terms of respecting life. If you're trying to build a culture of life, then you have to start from the very beginning of life, from conception, and you have to include how we think and act with regard to sexuality and contraception." Dr. Joseph B.Stanford, who was appointed by President Bush in 2002 to the F.D.A.'s Reproductive Health Drugs Advisory Committee despite (or perhaps because of) his opposition to contraception, sounded not a little like Daniel Defoe in a 1999 essay he wrote: "Sexual union in marriage ought to be a complete giving of each spouse to the other, and when fertility (or potential fertility) is deliberately excluded from that giving I am convinced that something valuable is lost. A husband will sometimes begin to see his wife as an object of sexual pleasure who should always be available for gratification."

As with other efforts - against gay marriage, stem cell research, cloning, assisted suicide - the anti-birth-control campaign isn't centralized; it seems rather to be part of the evolution of the conservative movement. The subject is talked about in evangelical churches and is on the agenda at the major Bible-based conservative organizations like Focus on the Family and the Christian Coalition. It also has its point people in Congress - including Representative Roscoe Bartlett of Maryland, Representative Chris Smith of New Jersey, Representative Joe Pitts and Representative Melissa Hart of Pennsylvania and Senator Tom Coburn of Oklahoma - all Republicans who have led opposition to various forms of contraception.

R. Albert Mohler Jr., president of the Southern Baptist Theological Seminary, is considered one of the leading intellectual figures of evangelical Christianity in the U.S. In a December 2005 column in The Christian Post titled "Can Christians Use Birth Control?" he wrote: "The effective separation of sex from procreation may be one of the most important defining marks of our age - and one of the most ominous. This awareness is spreading among American evangelicals, and it threatens to set loose a firestorm.. . .A growing number of evangelicals are rethinking the issue of birth control - and facing the hard questions posed by reproductive technologies."

It is difficult to state precisely when this rethinking began, but George W. Bush's victory in 2000, which was aided mightily by social conservatives, came around the same time that the abortion pill and the emergency contraception pill reached the market, and that convergence of events might be seen as the beginning of a new chapter in the culture war. State legislatures are debating dozens of bills surrounding emergency contraception, or the "morning-after pill": whether pharmacists have the right to refuse to fill orders; whether it should be made available over the counter; whether Catholic hospitals may decline to provide it to rape victims. To the dismay of many public-health officials, and following the will of conservative Christian organizations, the Bush administration has steadily moved the federal family-planning program in the direction of an abstinence-only-until-marriage program. Some conservative groups and some Republicans in Congress have waged a campaign against condoms in recent years, claiming they are less effective than popularly believed in preventing pregnancy and protecting against sexually transmitted diseases. Important international health experts say the Bush administration has used the government's program for AIDS relief to transmit its abstinence message overseas, de-emphasizing condoms and jeopardizing the health of large numbers of people, especially in Africa. A regulatory challenge has been filed with the F.D.A., and a push by some Republicans in Congress is under way to suspend the sale of the abortion pill (also known by the brand names RU-486 or Mifeprex) on the grounds that it is unsafe. The lead counsel in this challenge, however, admits the underlying motivation is opposition to abortion. Meanwhile, the abortion pill and the emergency contraception pill - because of their ease of use, the mechanisms by which they work and the fact that they are taken after sex - have blurred the line between contraception and abortion and have added a new wrinkle to the traditional anti-abortion movement.

Many Christians who are active in the evolving anti-birth-control arena state frankly that what links their efforts is a religious commitment to altering the moral landscape of the country. In particular, and not to put too fine a point on it, they want to change the way Americans have sex. Dr. Stanford, the F.D.A. adviser on reproductive-health drugs, proclaimed himself "fully committed to promoting an understanding of human sexuality and procreation radically at odds with the prevailing views and practices of our contemporary culture." Focus on the Family posts a kind of contraceptive warning label on its Web site: "Modern contraceptive inventions have given many an exaggerated sense of safety and prompted more people than ever before to move sexual expression outside the marriage boundary." Contraception, by this logic, encourages sexual promiscuity, sexual deviance (like homosexuality) and a preoccupation with sex that is unhealthful even within marriage.

It may be news to many people that contraception as a matter of right and public health is no longer a given, but politicians and those in the public health profession know it well. "The linking of abortion and contraception is indicative of a larger agenda, which is putting sex back into the box, as something that happens only within marriage," says William Smith, vice president for public policy for the Sexuality Information and Education Council of the United States. Siecus has been around since 1964, and as a group that supports abortion rights, it is natural enemies with many organizations on the right, but its mission has changed in recent years, from doing things like promoting condoms as a way to combat AIDS to, now, fighting to maintain the very idea of birth control as a social good. "Whether it's emergency contraception, sex education or abortion, anything that might be seen as facilitating sex outside a marital context is what they'd like to see obliterated," Smith says.

Senator Olympia Snowe of Maine, an abortion rights Republican who has sponsored legislation that would require insurance companies to cover contraception, has seen a major change. "Two decades or more ago, I don't think there was much of a divide on contraception and family planning," she says. "It was one area both sides could agree on as a way to reduce unwanted pregnancies. Now it becomes embroiled in philosophical disputes."

The Guttmacher Institute, which like Siecus has been an advocate for birth control and sex education for decades, has also felt the shift. "Ten years ago the fight was all about abortion," says Cynthia Dailard, a senior public-policy associate at Guttmacher. "Increasingly, they have moved to attack and denigrate contraception. For those of us who work in the public health field, and respect longstanding public health principles - that condoms reduce S.T.D.'s, that contraception is the most effective way to help people avoid unintended pregnancy - it's extremely disheartening to think we may be set back decades."

It was a Friday afternoon at the end of August last year, with most of official Washington on vacation, when a press conference was called at F.D.A. headquarters in Rockville, Md. The occasion was a major drug announcement, but no one from the agency's Center for Drug Evaluation and Research was in the room to hear Commissioner Lester M. Crawford declare that "the agency is unable at this time to reach a decision on the approvability of the application." It was for Plan B.

Plan B, the brand name for the most common form of emergency contraception, has been on the market since 1999 (another form, Preven, came on the market in 1998). The pill, which contains concentrated amounts of progestin, a hormone found in ordinary birth control pills, can prevent a pregnancy most effectively if taken within 72 hours of having sex. (The abortion pill, by contrast, can be taken up to 49 days after the beginning of the last menstrual period and causes the chemical abortion of a fetus.) Plan B's manufacturer applied in April 2003 for permission to sell Plan B over the counter. Reproductive and women's health professionals expected clear sailing for the drug (morning-after contraception has been available in some European countries for more than 20 years). Experts overwhelmingly considered it safe: in December 2003 the F.D.A.'s own joint advisory panel voted 28-0 that it was "safe for use in the nonprescription setting" and then voted 23 to 4 in favor of granting Plan B over-the-counter status.

The hope many people had for the drug was tied to an ugly number: 21. That is the number of abortions in the U.S. per year per 1,000 women of reproductive age, which puts the country at or near the top among developed nations. Put another way, according to a study released this past week by the Guttmacher Institute, there are 6.4 million pregnancies a year in the U.S., 3.1 million of which are unintended and 1.3 million of which end in abortion. In the seven years since the last such study, the overall unintended-pregnancy rate has remained unchanged; for women below the poverty level it increased 29 percent. If women had quick, easy access to a backup contraceptive, the thinking of Plan B proponents went, those rates - and thus the abortion rate - would drop. "I saw it as a win-win situation, something that everyone on both sides of the abortion issue could support," says Dr. Susan F. Wood, who was at the time director of the Office of Women's Health at the F.D.A. "I still don't get what happened."

One thing that happened, which Dr. Wood and many others may have failed to notice, was the change in conservative circles on the subject of contraception. At a White House press briefing in May of last year, three months before the F.D.A.'s nonruling on Plan B, Press Secretary Scott McClellan was asked four times by a WorldNetDaily correspondent, Les Kinsolving, if the president supported contraception. "I think the president's views are very clear when it comes to building a culture of life," McClellan replied. Kinsolving said, "If they were clear, I wouldn't have asked." McClellan replied: "And if you want to ask those questions, that's fine. I'm just not going to dignify them with a response." This exchange caught the attention of bloggers and others. In July, a group of Democrats in Congress, led by Representative Carolyn Maloney of New York, sent the first of four letters to the president asking outright: "Mr. President, do you support the right to use contraception?" According to Representative Maloney's office, the White House has still not responded.

For those who were listening, that silence may have given an indication of what had been going on inside the F.D.A. After the agency's advisory committees voted in favor of over-the-counter status for Plan B at the end of 2003, and after it was further approved at every level of the agency's professional staff, standard procedure would have been for the Center for Drug Evaluation and Research arm of the F.D.A. to approve the application. But one member of the F.D.A.'s Reproductive Health Drugs Advisory Committee had reservations: Dr. W. David Hager, a Christian conservative whom President Bush appointed to lead the panel in 2002. (After an outcry from women's groups, who were upset at Dr. Hager's writing that he used Jesus as a model for how he treated women in his gynecology practice, he was shifted from chairman of the panel to ordinary member.) Dr. Hager said he feared that if Plan B were freely available, it would increase sexual promiscuity among teenagers. F.D.A. staff members presented research showing that these fears were ungrounded: large-scale studies showed no increase in sexual activity when Plan B was available to them, and both the American Academy of Pediatrics and the Society for Adolescent Medicine endorsed the switch to over-the-counter status. Others argued that the concern was outside the agency's purview: that the F.D.A.'s mandate was specifically limited to safety and did not extend to matters like whether a product might lead to people having more sex. Meanwhile a government report later found that Dr. Janet Woodcock, deputy commissioner for operations at the F.D.A., had also expressed a fear that making the drug available over the counter could lead to "extreme promiscuous behaviors such as the medication taking on an 'urban legend' status that would lead adolescents to form sex-based cults centered around the use of Plan B." In May 2004, the F.D.A. rejected the finding of its scientific committees and denied the application, citing some of the reasons that Dr. Hager had expressed.

The drug's manufacturer reapplied two months later, this time for permission to sell it over the counter to women ages 16 and up, seemingly dealing with the issue of youth. Then, last August, Crawford made his announcement that the F.D.A. would delay its decision, a delay that could be indefinite. The announcement made headlines across the country. Dr. Wood, the F.D.A.'s women's health official, resigned in protest. Democrats in Congress asked for an investigation into what they felt was politics - the anti-birth-control agenda of the politically powerful Christian right - trumping science. The Government Accountability Office conducted a study of the events and issued a report last November concluding that the decision to reject the findings of the scientific advisory panel "was not typical of the other 67 prescription-to-O.T.C. switch decisions made from 1994 to 2004." Currently, Senators Hillary Clinton and Patty Murray are holding up the nomination of Andrew von Eschenbach as F.D.A. commissioner until the F.D.A. issues a verdict on the drug.

The saga of emergency contraception and the F.D.A. is developing into one of the iconic clashes of the Bush era: a story of the entanglement of politics, science and religious beliefs. At the heart of it is the question of whether emergency contraception is or could be a form of abortion. "The science is very clear that this does not cause an abortion," William Smith of Siecus told me. The same clarity exists on the other side. One of the "common and intended modes of action" of emergency contraception, according to the United States Conference of Catholic Bishops, "is to prevent the development of the embryo, resulting in his or her death." Dr. Gene Rudd, an obstetrician-gynecologist who is associate executive director of the Christian Medical and Dental Associations, advises his group's member physicians that "those who consider life to begin at fertilization recognize the pills' mechanisms as abortifacient," or inducing an abortion.

The issue is partly - but only partly - one of definition. According to the makers of the emergency contraception pill, it has three possible means of functioning. Most commonly, it stops ovulation - the release of an egg -or prevents sperm from fertilizing an egg. In some cases, however, depending on where a woman is in her cycle, it may stop an already fertilized egg from attaching to the uterine wall. In such a situation, for those who believe that life - and thus also pregnancy - begins at the moment of fertilization, it would indeed function as an abortifacient. According to the American College of Obstetricians and Gynecologists, however, pregnancy begins not at fertilization but at implantation. The medical thinking behind this definition has to do with the fact that implantation is the moment when a woman's body begins to nurture the fertilized egg. The roughly one-half of all fertilized eggs that never attach to a uterine wall are thus not generally considered to be tiny humans - ensouled beings - that died but rather fertilized eggs that did not turn into pregnancies. Federal regulations enacted during the Bush administration agree with this, stating, "Pregnancy encompasses the period of time from implantation until delivery."

People are, of course, perfectly within their rights to believe that pregnancy begins when sperm meets egg. And it is reasonable for groups like the Christian Medical and Dental Associations, Focus on the Family and the American Life League to want to alert their members that something billed as contraception might actually have a function that runs counter to their beliefs. But there are two twists. One is that emergency contraception may not actually work as an abortifacient. "There is no direct evidence that it blocks implantation," Dr. Wood says. "We can't tell for sure because very little research has been done on direct implantation of human eggs. You run into moral problems doing research on a woman's body and a human embryo. And since half of all fertilized eggs do not implant anyway, it would be difficult to know if this was the mechanism responsible." Still, if it's even possible for emergency contraception to stop implantation, then it's right for Dr. Rudd of the C.M.D.A. to advise his group's member physicians, "Regardless of what an assembly of experts define, or fail to define, as the beginning of pregnancy, if a patient retains the moral conviction that life begins at fertilization, she must be made aware of information relevant to that conviction."

But the other twist is that emergency contraception apparently works in a manner similar to that of the ordinary birth control pill. That is to say, the pill, which contains the hormone progestin, also has three possible means of operation: by stopping ovulation, preventing fertilization or impeding implantation. If emergency contraception is a potential abortifacient, then the same would seem to be true for the pill, which tens of millions of women have taken over the past several decades. Dr. Rudd disputed this. "The scientific evidence is that emergency contraception is more likely to have a post-fertility effect than the routine birth control," he told me. But Dr. James Trussell, director of the Office of Population Research at Princeton University and one of the world's leading experts on contraception, said: "That is completely wrong. The evidence is about the same for all hormonal methods of contraception. We can't rule out a post-fertility effect for Plan B, and the same is true for the birth control pill."

What's more, Dr. Trussell added: "There is evidence that there is a contraceptive effect of breast feeding after fertilization. While a woman is breast feeding, the first ovulation is characterized by a short luteal phase, or second half of the cycle. It's thought that because of that, implantation does not occur." In other words, if the emergency contraception pill causes abortions by blocking implantation, then by the same definition breast feeding may as well. Besides that, the intrauterine device, or IUD, can alter the lining of the uterus and, in theory, prevent implantation.

Ron Stephens is both a pharmacist and a Republican state legislator in Illinois, one of the states that are currently battlegrounds between pharmacists who claim the right to refuse to fill prescriptions for emergency contraceptives and women's and civil rights groups that argue that pharmacists must fill all prescriptions presented to them. Stephens not only supports the pharmacists' right of refusal but he also refuses to fill prescriptions for emergency contraception himself. He does, however, fill prescriptions for the birth control pill. When I asked him recently to explain his thinking on the two drugs, he said: "It's the difference between stopping a pregnancy from happening and ending a pregnancy. My understanding of the science is that the morning-after pill can end a pregnancy, whereas birth control pills will make a woman's body believe she is already pregnant so that the egg will not be fertilized." And what if studies show that, in fact, both drugs can prevent implantation? "Everyone has their natural prejudice," Stephens replied. "I'm going to understand it my way, and the issue is that you should not be forced to do something you believe is immoral."

If the pill and the IUD may prevent implantation, and if implantation is where anti-abortion groups draw the line, why haven't such groups railed against them for decades? Some have, but they got no traction. What happened, over the past 40 years, is that contraception became an accepted fact of life, and those who were opposed to it found themselves residing on the outer fringe.

In the current, evolving movement against contraception, therefore, some groups soft-pedal their position. "Concerned Women for America does not take a position regarding birth control," Wendy Wright, president of that influential, 500,000-member, biblically-based organization, told me. She went on to say, however, that C.W.A. does "educate regarding how certain birth control methods operate." Specifically, the group offers a brochure titled "High-Tech Birth Control: Health Care or Health Risk?" to those who call seeking guidance. Most methods of birth control can pose health risks. A 2005 World Health Organization study, for instance, found a connection between some forms of the pill and cancer. But the C.W.A. brochure goes well beyond this. Its section on emergency contraception advises that "its main function is to abort a living human embryo." One function of the birth control pill, it states, is to induce "a chemical abortion." The section on the IUD indicates none of its practical benefits (its 99 percent effectiveness in preventing pregnancy, its reversibility) and consists mostly of a litany of health complications, many of which health experts refute.

According to the Centers for Disease Control and Prevention, 98 percent of all women who have ever had intercourse have used at least one contraceptive method. Worldwide, about 76 million women currently use the birth control pill. It would be suicide for an organization that hopes to influence public policy to assert outright opposition to contraception. Instead, attacks are mostly around the periphery of the issue: on the health aspects of various forms of contraception, on the mechanism by which they work, on the efficacy of certain methods.

Why is this happening? What's the nature of the opposition to something that has become so basic a part of modern life?

One starting point is the Catholic Church, and especially Pope John Paul II, whose personal and philosophical magnetism revitalized Catholics around the world, especially the young. A series of reflections the pope gave between 1979 and 1984 on the "theology of the body" - his vision of the integrated physical, mental and spiritual human - has become a whole method of study within the church.

The pope was a trained philosopher, and the actual text of his addresses on the topic can be dense: "Masculinity and femininity - namely, sex - is the original sign of a creative donation and an awareness on the part of man, male-female, of a gift lived in an original way." But his words have been unpacked and pored over by theologians and students, and they have shaped a new approach to sex that is, in many ways, old. Kimberly Zenarolla, for one, is applying the theology of the body to the American political sphere. She is the director of strategic development for the National Pro-Life Action Center, a two-year-old organization with 10,000 members that lobbies on abortion, euthanasia, stem cell research and contraception. She's also a single 34-year-old who lives in Washington with, as she put it, "a group of young professionals who are living the countercultural message of chastity to its fullest expression."

Zenarolla told me she converted to Catholicism two years ago: "I tell people I became Catholic because of the church's teaching on contraception. We are opposed to sex before marriage and contraception within marriage. We believe that the sexual act is meant to be a complete giving of self. Of course its purpose is procreation, but the church also affirms the unitive aspect: it brings a couple together. By using contraception, they are not allowing the fullness of their expression of love. To frustrate the procreative potential ends up harming the relationship."

The Catholic Church sanctions "natural family planning," otherwise known as the rhythm method, but it holds that artificial means of contraception lead people to see the body as an instrument, reducing human dignity and making them slaves to their desires. As Pope Benedict XVI wrote when he was Cardinal Ratzinger, "Contraception and abortion both have their roots in [a] depersonalized and utilitarian view of sexuality and procreation - which in turn is based on a truncated notion of man and his freedom." American Catholics have overwhelmingly disagreed: a Harris Poll in 2005, for instance, found that 90 percent of Catholics (as compared with 93 percent of all Americans) support the use of contraception. (On April 23, a Vatican spokesman indicated that Pope Benedict XVI would soon issue a new document on condoms, which some people have speculated could for the first time give the church's blessing to the use of condoms to prevent the spread of disease, but not intentionally as a form of contraception. This may seem a fine distinction, but Vatican watchers say that the church could adopt it as a lesser-of-two-evils principle.)

Further, the church holds that contraception and in vitro fertilization are two sides of the same coin: both are attempts to manipulate sexuality to serve the selfish demands of the individual. "I can sympathize with a couple who can't conceive and desperately want a child," Zenarolla says. "But if you examine in vitro fertilization, you begin to see what an objectification of the body it is. Today there are 400,000 leftover frozen embryos. That clump of cells is a human being, with its own DNA. Whenever we take it out of the safe harbor of its mother's womb, it opens up life to manipulation and control: 'I want a boy with blue eyes and no diseases."' The objectification of the human, she says, then transfers to the child. "It leads to eugenics," Zenarolla told me, "to wanting to get rid of people who have defects. It's part of the devaluation of human beings."

From this perspective - essentially that of the strict Catholic - this is the dark future toward which secular society is heading. Bishop John W. Yanta of the Diocese of Amarillo, Tex., who oversees an organization founded last year to train priests in the "Gospel of Life," has called contraception "intrinsically evil" and "a big part of the culture of death."

Some Protestants have come to a similar view recently. Mohler, president of the Southern Baptist Theological Seminary, explains the evolution of modern evangelical thought on contraception this way: "When the pill came out, evangelicals were very much a part of mainstream American culture, and like others they saw technology as a gift. There was a vaccine to fight polio. The pill was seen in the same light. I think evangelicals thought, Catholics can't use it, but we can: aren't we lucky?"

But then, from this perspective, the pill began to do terrible damage. "I cannot imagine any development in human history, after the Fall, that has had a greater impact on human beings than the pill," Mohler continued. "It became almost an assured form of contraception, something humans had never encountered before in history. Prior to it, every time a couple had sex, there was a good chance of pregnancy. Once that is removed, the entire horizon of the sexual act changes. I think there could be no question that the pill gave incredible license to everything from adultery and affairs to premarital sex and within marriage to a separation of the sex act and procreation."

That may be a distinctly minority position, but some who work in the public health field acknowledge that the social conservatives have a point. "I think the left missed something in the last couple of decades," says Sarah Brown, president of the National Campaign to Prevent Teen Pregnancy, which positions itself as a moderate voice in the heated world of reproductive politics. "With the advent of oral contraception, I think there was this great sense that we had a solution to the problem of unintended pregnancy. But that is a medical model. I think the thing that was missed was that sex and pregnancy and relationships aren't just a health issue. They are really about family and gender and religion and values. And what the right did was move in and say we're not just talking about body parts."

Mohler says the awareness of the damage being caused by what he and others call "the contraceptive mentality" is felt most acutely today by younger evangelicals: "I detect a huge shift. Students on our campus are intensely concerned. Not a week goes by that I do not get contacted by pastors about the issue. There are active debates going on. It's one of the things that may serve to divide evangelicalism."

Eventually, all roads lead to abortion. Once, the definition of abortion was simple - a surgical procedure to extract a fetus - and with the advent of technology that allowed imaging of the fetus within the womb, abortion opponents found they had a powerful tool; photographs of "preborn babies" with human features were common in anti-abortion campaigns. Building on this, and mindful of the difficulty of overturning Roe, they developed an incremental strategy for containing abortion, which has been very effective. Last year, 52 state laws were passed restricting abortion. Currently, more than 100 new state measures are being considered that would limit the procedure, either by making it more difficult to obtain an abortion or by compelling women to reconsider. Nationally, a bill called the Fetal Pain Awareness Act, sponsored by Senator Sam Brownback of Kansas, would require a woman seeking an abortion to be told that, as of 20 weeks, a fetus can feel pain, and that she be offered the option of providing it with painkillers. It has not gotten through Congress, and the science of the "pain age" is hotly disputed, but four states have adopted similar legislation. The Unborn Victims of Violence Act, which President Bush signed in 2004, makes a violent attack on a pregnant woman two crimes: one on the woman and one on her unborn child. It was denounced by abortion rights groups as a step toward granting full legal status to a fetus.

This slow, steady campaign has made an impact on the country at large: polls show that while most people still support Roe, they have deep misgivings about abortion and tend to support restrictions on it, like parental consent and late-term (or partial-birth) bans. One threat to this strategy, according to some on the right, is South Dakota's passage of an abortion ban, which is meant as a direct challenge to Roe.

But the new abortion and contraceptive drugs have changed the dynamic as well. Because the abortion pill operates before a fetus has developed babylike features, it "takes away some ammunition" from the anti-abortion advocates, says Cynthia Dailard of the Guttmacher Institute. Imaging technology helped anti-abortion forces to personify the fetus, and recent tactics that abortion foes have pursued tend to be focused on an older fetus. Such is the case with the Partial Birth Abortion law, which President Bush signed in 2003. It was subsequently declared unconstitutional, but the Supreme Court will take it up again later this year. The new drugs, however, threaten to undercut such efforts. The battle line, in other words, is shifting backward, from viability to implantation. The abortion pill, which has been on the market since 2000, is under attack, with a group of Republicans in Congress calling for its suspension, in the wake of the deaths of five women who took it.

Democrats, meanwhile, have had their difficulty with the abortion issue, and their new hopes are pinned to a strategy that focuses on contraception as a way to reduce unintended pregnancy. Last month, Senators Harry Reid and Hillary Clinton - an anti-abortion Democrat and an abortion rights Democrat - introduced legislation that would require insurance companies to cover contraceptives. In part, the idea is to force Republicans to support contraception or be branded as reactionaries. The conservative counter was that giving even more government backing to emergency contraception and other escape hatches from unwanted pregnancy will lead to a new wave of sexual promiscuity. An editorial in the conservative magazine Human Events characterized the effect of such legislation as "enabling more low-income women to have consequence-free sex."

Some not-very-attentive college kids spending spring break in Fort Lauderdale got a shock when they wandered into a tent on the beach last March. The sign welcoming passers-by actually said, "Girls Gone Mild." Inside they found a few dozen young people drinking bottled water, some wearing T-shirts that said, "Pet Your Dog, Not Your Date," others perusing a chart about S.T.D.'s.

If there is a place where anti-birth-control conservatives speak their subtext regarding sex, it is in the abstinence movement, where the message is "just don't do it." Federal support for abstinence education in schools - which teaches kids the benefits of saving their virginity until marriage - began in 1981, but the program muddled along for years and was tangled for a time in a lawsuit filed by the American Civil Liberties Union that charged that it was explicitly Christian in context. Under President Bush, spending increased significantly: the 2007 budget calls for $204 million to support abstinence programs (up from $80 million in 2001).

Leslee Unruh, a 51-year-old former motivational speaker who says that her life was transformed in 1984 by the psychological devastation wrought by having an abortion, is the doyenne of the abstinence movement. She has dedicated herself to fostering in teenagers a holistic approach to relationships. Like many in the abstinence movement, Unruh says she believes that society is unhealthily focused on sex and that dwelling on contraception makes it worse. "I see the problem as a lack of teaching about relationships: how to bond with the person you're going to have a relationship with, so that it's something that's good for you," she says. "We teach kids it doesn't have to be physical."

In addition to providing an information center for the abstinence industry that has blossomed in recent years, she takes her message directly to kids. Besides "Girls Gone Mild," she sponsors "Purity Balls," which fathers attend with their teenage daughters. "We think the relationship between fathers and their daughters is the key," she told me. At the purity ball, a father gives a "purity ring" to his daughter - a symbol of the promise she makes to maintain her virginity for her future husband. Then, during her marriage ceremony, the daughter gives the ring to her new husband. Abstinence Clearinghouse's Web site advertises the purity ball as an event "which celebrates your 'little girl' and her gift of sexual purity."

The intellectual force behind the abstinence-education movement is Robert Rector, senior research fellow at the Heritage Foundation. Rector wrote some of the federal legislation mandating abstinence education, and he worked on a number of studies that purport to demonstrate its effectiveness. One component of abstinence education is the "virginity pledge," and Rector is an author of one study that concluded that teenagers who take virginity pledges "have substantially improved life outcomes," and another that showed that "sexually active teenagers are more likely to be depressed and to attempt suicide."

The idea of promoting abstinence over comprehensive sex education (which includes information on various forms of contraception and how to use them) gets to the core of the expanded conservative approach to birth control issues. It really is all about sex. "There are two philosophies of sexuality," Rector told me. "One regards it as primarily physical and all about physical pleasure. Therefore, the idea is to have lots of physical pleasure without acquiring disease or getting pregnant. The other is primarily moral and psychological in nature, and stresses that this is the part of sex that's rewarding and important."

Rector says that abstinence programs can't properly be combined with other elements in a comprehensive sex education program because the message is lost when a teacher says: "One option you might want to consider is abstaining. Now let's talk about diaphragms."

Abstinence education, meanwhile, gets withering criticism from the other side. "There is still not a single, sound peer-reviewed study that shows abstinence programs work," says William Smith of Siecus. Peter Bearman, director of the Institute for Social and Economic Research and Policy at Columbia University, who has analyzed virginity pledge programs including Rector's, says: "The money being poured into these programs is out of control. And the thing is this is not about public health. It's a moral revolution. The goal is not stopping unwanted pregnancy but stopping sexual expression."

A December 2004 report on federally financed abstinence-only programs conducted by the office of Representative Henry Waxman, Democrat of California, charged that the major programs presented misleading information about health (one curriculum quoted in the report stated that "condoms fail to prevent H.I.V. approximately 31 percent of the time"), state beliefs as facts (the report cited a curriculum that refers to a 43-day-old fetus as a "thinking person") and give outmoded stereotypes of the sexes.

All parents struggle with how to shield their children from the excesses of popular culture, and not surprisingly, surveys show that most want teenagers to delay first intercourse. But by wide margins they also say kids should be taught about contraceptives. A poll released in 2004 by National Public Radio, the Kaiser Family Foundation and Harvard's Kennedy School of Government found, for example, that 95 percent of parents think that schools should encourage teenagers to wait until they are older to have sex, and also that 94 percent think that kids should learn about birth control in school.

The Bush administration's point man on abstinence - Jeffrey Trimbath, the director of Abstinence Education in the Family and Youth Services Bureau of the Department of Health and Human Services - declined through a spokesman to speak with me and referred me instead to Rector. Rector sought to refute the Waxman report, saying that some of what was cited as flawed information in curricula did not come from abstinence curricula at all, but from other sources. The first major evaluation of abstinence education - a Congressionally-authorized study being conducted by Mathematica Policy Research - is due to be completed later this year.

Abstinence has also become a primary element of Pepfar, President Bush's overseas AIDS relief program - with, some experts say, disastrous results. The Government Accountability Office released a study in April that found that in many countries administrators were forced to cut funds intended to fight mother-to-child H.I.V. infection in order to finance abstinence programs. Stephen Lewis, the United Nations special envoy for H.I.V./AIDS in Africa, who had previously charged that the Bush program put "significant numbers" of people in Africa at risk, told me: "I feel vindicated by the G.A.O. study. I think it raises legitimate questions about the disproportionate attention given to abstinence as opposed to condoms. At this moment, even the Catholic Church is reconsidering condoms." On April 7, the State Department issued its own response to the G.A.O. study, in which it claimed that as a result of approaches like the Bush administration's "ABC policy" - promoting "abstinence" and "being faithful," then "condoms" - H.I.V. transmission has fallen in Uganda, Zimbabwe and Kenya and "male faithfulness" has increased.

On the domestic front, the rise in abstinence education has been paralleled by a tendency on the part of some conservatives to denigrate condoms. Senator Tom Coburn of Oklahoma, who is also an obstetrician, has led a campaign to force condom makers to indicate on their labels that they may not prevent certain S.T.D.'s, specifically the human papillomavirus. In 2001, when he was in the House of Representatives, he issued a press release entitled "Condoms Do Not Prevent Most S.T.D.'s." Sex educators say this is a twisting of data to suit an ideologically driven anti-sex agenda. "An N.I.H. panel said condoms are impermeable to even the smallest S.T.D. viruses," Cynthia Dailard of Guttmacher says.

Senator Coburn told me that he's not anti-birth-control: "I'm not a no-condom person. I prescribe tons of birth control products. But that's only one-half of the issue. The other half is preventing S.T.D.'s." This is not the message of the federal abstinence initiative, however. The emphasis there is squarely on promoting a moral framework that puts sexuality in a particular place. As the 2007 federal guidelines for program financing state, "It is required that the abstinence education curriculum teaches that a mutually faithful monogamous relationship in the context of marriage is the expected standard of human sexual activity."

Social conservatives in the U.S. seem to be moving in the opposite direction from much of the rest of the world. At least 12 countries have liberalized abortion laws in recent years. Emergency contraception is currently available without a prescription in more than 40 countries. In much of Western Europe, abortion and contraception are available and fully covered by insurance.

The dark side of this, according to some commentators, is the declining birth rate in Europe. It takes an average of 2.1 children per woman to keep a population constant. Italy and Spain are tied for the lowest fertility rate in Western Europe, at 1.28. Even Ireland, the country with the highest birth rate, at 1.86, is suffering a population drain. (The U.S. rate is 2.09.) From 1994 to 2004, the average age at which European women became mothers rose by about 16 months, to 28.2. This, according to social conservatives, is the black hole into which the contraceptive mentality is drawn. As the Canadian priest Raymond J. de Souza wrote in National Review in 2004, "If children are a sign of hope in the future, Europe - and to a lesser extent Canada, Australia and the United States - is losing its will to live."

This would seem to be a bind, because the benefits of family planning are profound: couples can organize their lives, financially and otherwise, when they are able to choose when to have children and how many to have. And, around the world, countries in which abortion is legal and contraception is widely available tend to rank among the lowest in rate of abortion, while those that outlaw abortion - notably in Central and South America and Africa - have rates that are among the highest. According to Stanley K. Henshaw of the Guttmacher Institute, recent drops in abortion rates in Eastern Europe are due to improved access to contraceptives. The U.S. falls somewhere in the middle in rate of abortion: at 21 per 1,000 women of reproductive age, it is roughly on par with Nigeria (25), much better than Peru (56) but far worse than the Netherlands (9).

The Netherlands, where the teen pregnancy rate also ranks among the lowest in the world, has long been of interest to sex educators in the U.S. for the frankness of its approach. The national sex education course, called Long Live Love, begins at age 13. One of its hallmarks has been dubbed "Double Dutch" - encouraging the use of both condoms and birth control pills. "It's proven successful," says Margo Mulder of STI AIDS Netherlands, the Dutch health education center. "It shows that when you discuss contraception and protection with students, they actually are careful. And I know that some people in the U.S. say that when you promote contraception, you're also promoting sex, but we've found that when you educate people, they don't have sex earlier. They think about it. So you're not promoting sex, you're helping them to be rational about doing it."

The problem with this, as far as American social conservatives are concerned, is that it treats symptoms rather than what they see as the underlying disease: an outlook that is focused on the individual at the expense of family and society. Their ultimate goal is not a number - the percentage of abortions or unintended pregnancies - but an ideal, a way for people to think and behave. As Mohler says of the Dutch approach in particular: "The idea is to completely sever the sex act from reproduction, and then train teens to do it. It treats sex as a morally meaningless act. I find it profoundly anti-humanistic."

While Americans as a whole don't hold such a dark view of comprehensive sex education, many do feel there's something wrong with a strictly clinical approach. This ambivalence, according to Sarah Brown of the National Campaign to Prevent Teen Pregnancy, gets to the root of the problem and may explain the numbers. "One of the things I'm most often asked is why the abortion and unintended pregnancy rates are so much lower in Europe," she says. "People talk about the easy access to contraception there, but I think it's really a matter of the underlying social norms. In Europe, these things are in the open, and the only issue is to be careful. Here in the U.S., people are still arguing about whether it's O.K. to have sex."