Today the Food and Drug Administration approved U.S. use of the drug mifepristone, or RU-486, which causes chemical abortions. Controversy about this substance, widely available in Europe for years, will now move to the center stage of the pro-life/pro-choice battle, including, surely, into the presidential debates. Al Gore has said that he favors availability of RU-486; George W. Bush opposes abortion and has said he would oppose mifepristone as well.

Mifepristone isn't a "morning after" pill that prevents pregnancy; in combination with another, already available chemical, it triggers an abortion in someone who is already pregnant, essentially by causing a miscarriage. So reaction to this new drug is likely to split along standard pro-life/pro-choice lines.

But should it? Because RU-486 does have one ethical point in its favor--it shifts the focus of abortion toward the earliest weeks of pregnancy, when the moral questions are least perilous. Abortion may be right or wrong, but if you're going to have an abortion, using RU-486 reduces the moral risk.

First, what mifepristone does. Pregnancy does not actually commence until several days or even a few weeks after conception, when the zygote implants in the uterine wall. It's the implantation, not the conception, that sends the woman's body the hormonal message to become pregnant. Mifepristone can prevent implantation by blocking the necessary hormone progesterone; it can also disrupt early pregnancy in which a zygote has implanted but only barely begun to become a fetus. Two days after swallowing RU-486, a woman takes misoprostol, a chemical already on the market that causes contractions. Combined, these two drugs essentially trigger a miscarriage.

Existing sides in the pro-life/pro-choice debate have tended to fixate on RU-486's clinical uses. The drug allows women to have an abortion without undergoing a surgical procedure, thus making abortion safer and more "think-able" for some women (though RU-486 is not safe for some women for medical reasons). Chemical abortion makes what happens more private for the woman: The induced miscarriage happens at home, not in a clinic. Although the FDA regulations being published with the drug say that an RU-486 abortion should be accomplished by three separate visits to a doctor's office, in which the physician administers the doses, in practice there will be no way to prevent doctors from simply handing the pills to women and instructing them on when to take them. Women would then return for a follow-up visit, as they would after a natural miscarriage.

To the pro-choice side, the non-surgical nature of RU-486 is a huge plus: More private and less invasive, the abortion becomes less stressful for the woman. Though still unpleasant: Miscarriages natural or induced are often accompanied by pain, bleeding, and psychological anguish. To the pro-life side, anything that makes abortion more private may encourage women to go ahead, especially if they can skip that traumatic moment of entry into a surgical clinic. The pro-life side is also upset that the FDA, which certifies drugs for saving or prolonging life, has for the first time certified a drug for termination of life.

So for anyone who takes one of the two polar views of abortion--either that life begins at conception and all abortion is always wrong, or that life begins at birth and anything that happens before is the woman's choice--mifepristone changes nothing.

But for the millions of Americans who are conflicted on abortion, uncomfortable with its occurrence but also uncomfortable with denying women the control of their own bodies, RU-486 is good news. And for this simple reason: It can only work in the first six weeks or so of pregnancy, the time when moral questions are least pronounced. And for those millions who are conflicted about abortion, there is a huge, huge difference between early and late pregnancy.

Research increasingly shows that fetuses in the third trimester, in addition to being well-developed and usually able to live outside the mother, have brain-wave functions that suggest the fullness of life; this increasingly makes the late-term abortion morally repugnant even to those who support basic Roe rights. (For more on brain-wave research and the legal status of preserving Roe but restricting late-term abortion, see http://www.tnr.com/013100/easterbrook013100.html.) In the second trimester of pregnancy, moral questions are mixed: The fetus is recognizably human but can't live outside the mother and has none of the complex brain-activity patterns that neurologists search for when trying to determine if an adult's mind is alive or has died.

In the first trimester, however, the moral quandaries seem least compelling. Up to the point at which RU-486 works, the fetus is not recognizably human. It has no brain activity, just random firings of nerve synapses in developing tissue. What's happening in a woman's uterus at that point clearly has the potential for life, but so do frozen sperm and frozen eggs in a laboratory storage rack. If the soul is conferred at conception, then abortion by RU-486 would be just as wrong as any other kind of abortion. But if the soul gradually develops along with the child--and the Bible tells us nothing about when the soul is formed; soul-at-conception is a church rather than scriptural doctrine--then early abortion is clearly preferable to any other kind.

When the standard polar positions of the pro-life/pro-choice debate are stripped away, what is significant about mifepristone is not the chemical-surgical distinction, but the fact that this form of abortion only works in roughly the first six weeks. If abortion is to be legal, anything that shifts the procedure as early as possible in pregnancy reduces the moral hazard. So the debate regarding whether there should be an abortion right will go on. But if there is to be such a right, RU-486 is much to be preferred over other abortion forms.

And maybe it could all lead to a political compromise: The legalization of mifepristone, which increases women's freedom at the early stage of pregnancy when abortion is most defensible morally, in return for legislation to eliminate almost all abortion in the third-trimester, when the fetus has become a baby and needs legal protection.