Some messages can't be massaged.

COMMUNICATIONS AND "MESSAGING" PLAY A LARGER part in politics and social policy than at any time in history. In the U.K., as in the U.S., it seems that policymakers spend more time trying to work out how to "sell" initiatives to the public than assessing how effective they would be if they were adopted. "Will it win support?" seems more important than "Is it true?" or "Will it work?" Naturally, this affects and frames the abortion discourse on both sides of the pond.

Prochoice advocates know we must move on from the slogans of the past, because today's social concerns are different. The advance of reproductive technologies and fetal medicine has stimulated an interest in the development of life before birth that did not exist 30 years ago. In the 1970s, abortion was seen as an issue affecting a woman ("our bodies, our lives, our right to decide"); now public opinion is increasing concerned with the fetus (does it feel pain? have rights?). In the 1970s, women's equality was an ambition to be fought for; now many believe it has been achieved. The language of the "right to choose," which once seemed central to women's freedom, now makes many people uncomfortable.

We must address this discomfort. To do this, we have to engage with contemporary concerns, and we can all agree that research that examines what alienates people from prochoice perspectives is vital to such engagement. However, there is a danger that we may become so concerned with "branding" that we lose sight of what we stand for. We do ourselves no favors--and much fault--when, in the hope of framing abortion to make it acceptable to the widest constituency, we forget essential truths. One of these truths is that access to abortion underpins, and is essential to, women's equality.

It seems unfashionably fundamentalist to defend the notion that women should have a "right" to abortion. It does not play well with members of the public who misunderstand what it means. This is not surprising. Today, we talk imprecisely about the "right" to many things--the right to be happy, the right to be stress-free, the right to have our views respected. But this promiscuous use of the term degrades the concept of a "right." For those of us who emerged from a progressive, humanist tradition, "rights" designates the requirements for participation in bourgeois, democratic society. Rights are what are required to make people equal. Thirty years ago, this specific concept of rights was shared by democrats and those concerned with social justice. The right to abortion and contraception was a basic tenet of the women's liberation movement in its early years, along with the right to equal pay and equal job opportunities, because activists understood that women needed control over their fertility to play an equal role in public life. When you deny me a means to end my unwanted pregnancy, you deny me the opportunity to participate in society in the way that my brother or husband can. Better nurseries and better financial support can mitigate some of the consequences of motherhood, but nothing can mitigate the impact of pregnancy itself, which is why women need the means to end it.

This has not changed: It is as true in 2006 as it was in 1976. Contraception has improved, but is still fallible. Abortion is a necessary back-up to birth control for any society that is committed to equality of opportunity for women. The discourse of women's equality may have changed, but its fundamental prerequisites have not.

There is also another way in which the right to abortion must be nonnegotiable. When we are denied the right to end pregnancy, we lose our right to bodily autonomy, a fundamental human right central to Western civilization. The ethics of modern medical practice is built on the notion that each of us has the right to refuse to compromise our bodily integrity. You might find it morally reprehensible for me to refuse to give up a kidney that could be transplanted to save the life of my son, but there is no law to force me to do it. In the U.K., the same is true of birth decisions. In refusing a Caesarean section, I may condemn my unborn baby to certain death, but I commit no crime in doing so. No doctor can force me to accept a medical intervention against my consent, unless I am mentally incompetent. The law forces us to draw a distinction between what is legal and what we regard as morally right and wrong. We accept this because we accept that to compel nonconsensual medical intervention in the interest of a third party is a greater social evil than an occasional unpalatable individual choice.

This unfashionable privileging of rights is not divorced from the more acceptable stress on responsibility. Surely it is right, if not "a right," for women to be allowed to make their own moral choices concerning their pregnancies. The decision must be made by someone; why should it not be made by the person whose life is most connected to it? Ronald Dworkin argues compellingly in his Life's Dominion that part of our belief in human dignity rests on people's having "the moral right and moral responsibility to confront the most fundamental questions about the meaning and value of their own lives for themselves." Each of us must be answerable to his own conscience and conviction; this, Dworkin argues, is part of what makes us human. To take away our responsibility for our moral decisions is to take away our humanity.

This is somewhat inconvenient to those trying to construct a popular and populist argument for legal abortion. It implies we must allow people to make decisions that we believe are wrong--because it would be more wrong for us to deny them the capacity to do that. As Dworkin argues eloquently, "Tolerance is the cost we must pay for our adventure in liberty."

This statement of principle is unlikely to score well in focus groups or to gain traction even among many who would regard themselves as prochoice. I am not suggesting that we insist on a principled defense of liberty during our future struggles to keep abortion legal. But we should be mindful of why, in the past, we argued for abortion as a right. It was not because we were less sensitive, less educated, less tactical and less subtle than now, but because we needed to explain why abortion mattered. We still do, even if we need to do it in a different way in a social climate less inclined to adventure in liberty.

Of course, we can be pragmatic--we don't have to talk in the language of rights. The U.K. provides an interesting example of abortion access expanded and improved by a political administration that situates abortion not as a right, but a public health concern. In the U.K., participants in the abortion discourse have been almost silent as to rights. Since abortion was legalized in the 1960s, it has been treated as a matter of public health. Abortion access has been accepted as a way to address social problems of deprivation and exclusion, to reduce the number of "unfit parents" and "problem families." The framing of abortion in a personal and public health context has made it difficult to oppose. When abortion is seen as a health matter, to argue against abortion is to argue against a doctor's decision of what is best for a patient.

In Britain today, there is a social consensus that children should be planned and wanted and that parents should be responsible. It is accepted that contraception sometimes fails that couples sometimes fail to use it. Unplanned, unwanted pregnancy is seen as a consequence of modern life. In 2005, the government committed itself to an assessment of the consequences that would follow from making abortion unlawful. In a cost analysis of potential legislation that would make abortion illegal except in cases of risk to life or rape, the benefit of such a law was held to be that it "provides a social-moral benefit to members of the public that are pro-life and disagree with the principle of abortion"; banning abortion in this way was not seen as conferring a social-moral benefit on society as a whole. The cost of enactment was estimated as follows: "750 million [pounds sterling] a year net financial costs, high risk of up to 15 deaths a year, 15,000 extra teenage mothers a year, 12,000 children a year neglected/abused." The parliamentary undersecretary of state for public health signed to indicate she believed this a fair comparison of the costs and benefits.

The public health arguments for abortion have potential to unite social liberals and conservatives. Even those who think abortion is abhorrent draw back from the practical consequences of making it unlawful. In the U.K., there is a broad consensus that abortion is a "lesser evil," a wrong that is sometimes right.

The opportunism of leading on public health is understandable, even forgivable, provided we remain mindful of the rights issues that stand silently in the shadows. We must remain aware of them, lest the public health benefits of abortion cause conservatives to become overzealous as to abortion's role in reducing the costs of unwanted births to "problem" families. Just as we must tolerate those deciding to have abortions that we may think are wrong, so our defense of the right to bodily autonomy compels us to defend a woman's right to continue her pregnancy. Acknowledgement and respect for this is what separates us from Neo-Malthusians who see abortion as a social solution to poverty and disadvantage.

It may be that the arguments around pubic health are where we can establish the greatest consensus on abortion's acceptability. However, any such consensus will be partial, because the moral dimension will remain contentious. This is inevitable and insurmountable. There can be no moral consensus that includes those who believe that the destruction of human life in the womb is wrong and those who believe it is not. It may be possible to establish a pragmatic consensus among those who are prepared to discuss which abortions are less wrong than others, but attempts to establish foundations for a broader moral consensus degenerate into glibness.

Take journalist Will Saletan's suggestion, in his much-discussed New York Times op-ed piece of January 22, 2006, that to galvanize public sentiment, we should adopt the principle that "abortion is bad, and the ideal number of abortions is zero." It is difficult to see how this engages the discussion in a meaningful way at all, given that no one argues that "abortion is good, and the ideal number of abortions is a million." Even those of us who believe that abortion is a right understand that women do not exercise their right to abortion in the same way that they exercise their right to vote. We can acknowledge that access to abortion is a social good while acknowledging that it's a bad experience for an individual woman to have one. Whatever the sociopolitical meaning of abortion, for an individual woman, it is her private solution to her individual problem.

For sure, we can win agreement that it would be good if abortion didn't exist. But this is about as meaningful as a consensus that the ideal number of poor people is zero. Bob Geldof and Bono recently discovered that it is easy to get people to say they want to "make poverty history"--who did they think would argue for keeping poverty contemporary?--but that agreement on how to achieve that is nearly impossible. So it is with abortion; the devil is in the details. The public knows this, even if communications consultants pretend it doesn't--which is why, often, the arguments that "play well" in focus groups play less well outside them.

The morality of abortion cannot be resolved in the abstract. Each individual abortion takes place within its own complex set of circumstances. To understand abortion, we need to understand its place in women's lives. It may be that we can best build support for legal abortion by putting the spin to one side and telling the whole truth: the truth about what abortion is, the truth about why women have abortions and the truth about what it means for women when bodily autonomy is denied. Maintaining support for legal abortion is not about messaging--it is far more complex and important than that. To defend abortion, we must win arguments in favor of tolerance and encourage an aspiration for liberty. To win the arguments, first we must have them.

ANN FUREDI is the chief executive of bpas, the U.K.'s largest independent abortion provider.