Under a 1988 Vatican ruling, "abortion" is defined as any method used to terminate a pregnancy from the moment of conception. Abortion thus understood is always illicit, according to the official discipline of the Catholic church, and can trigger excommunication for the parties involved.

The church's condemnation of abortion includes not only interventions to remove a fetus before birth, but the use of all abortifacients, including intrauterine devices and certain types of birth control pills that prevent implantation or stimulate uterine contractions to reject a fertilized egg. It also encompasses drugs such as RU486, called the abortion pill, which provokes miscarriages by blocking progesterone in the first weeks of pregnancy.

This expansive standard is expressed in a May 23, 1988, ruling from the Pontifical Council for the Interpretation of Legislative Texts, the Vatican office charged with authoritative interpretations of canon law. The council was responding to a dubium, or request for clan ification, from a bishop on canon 1398, which stipulates excommunication as the penalty for abortion.

The ban on abortion, in the sense of the deliberate termination of a pregnancy, is absolute.

According to Redemptorist Fr. Brian Johnstone, a bioethics expert at Rome's prestigious Alphonsian Academy, the lone situation in which the removal of a fetus may be tolerated by official Catholic teaching is if the mother urgently requires a life-or-death procedure with the unwanted consequence of ending her pregnancy. A pregnant woman with advanced-cervical cancer, for example, could have an operation to remove the cancer, which would also mean removing the fetus. In Catholic moral theology, this is understood as the principle of "double effect." The positive effect, saving the life of the mother, is what is intended, while the negative effect, the death of the fetus, is merely foresee.

There are recent cases in Italy, Johnstone said, in which women in similar circumstances have chosen to continue with their pregnancies. In some of these cases, he said, the child was born healthy while the mother died. The church admires such sacrifice, Johnstone said, but it does not oblige anyone to make this choice.

While the deliberate removal of a fetus has always been banned, Johnstone said, historically there has been debate among Catholic theologians as to whether all such acts qualify as "abortion," in the sense of homicide, or whether termination of pregnancy at an early stage is more akin to contraception.

St. Augustine wrote in the fourth century that abortion could be viewed as murder only if the fetus was judged a "fully formed" human. That stage of development, "hominization," occurred for Augustine some time after conception - 40 days for males and 80 days for females. St. Thomas Aquinas, the 13th-century Dominican theologian, likewise held that "infusion" of the human soul took place between 40 and 80 days after conception, following the biological views of the Greek philosopher Aristotle.

The interruption of a pregnancy prior to this point was for Augustine, Aquinas and those who followed them, Johnstone said, a particularly grave form of birth control rather than abortion.

This tradition held until Pope Sixtus V, a Franciscan and reformer of moral standards in the Papal States, who in 1588 decreed excommunication for any termination of a pregnancy from the moment of conception. His motive, according to Johnstone, was to crack down on prostitution in Rome. The campaign was a failure, and three years later Gregory XIV reversed the edict. Finally, in 1869, Pope Pius IX sidestepped the ho- minization debate and declared that the fetus, "although not ensouled, is directed to the forming of man. Therefore, its ejection is anticipated homicide" at any stage of pregnancy and incurs excommunication.

Johnstone stressed that there was never any question of whether terminating a pregnancy was sinful, but rather what kind of sin it was in the early stages - homicide or something else. Hence it would be inaccurate to say that the church ever "permitted" abortion.

Today, Canon 1398 of the 1983 revision of the Code of Canon Law reads: "A person who actually procures an abortion incurs a latae sententiae excommunication." The word "actually" indicates that the abortion must have been successful for the penalty to occur; the mere intent to have an abortion is not sufficient.

That the penalty is latae sententiae means it is automatic, and hence there is no need for an official decree. Most excommunications, by way of contrast, have to be proclaimed by church authorities in order to take effect; these are called feren- dae sententiae. There are seven acts in canon law that trigger latae sententiae excommunication. Aside from abortion, they are: violence against the pope; sacrilege such as throwing away a consecrated host; absolving a person with whom one has sinned against the sixth commandment; consecrating a bishop without authorization; violating the seal of confession; and apostasy, heresy or schism.

Canon 1329 specifies that accomplices to an act that triggers a latae sententiae excommunication are also subject to the same penalty if "without their assistance, the crime would not have been committed." Canonists believe such accomplices include the doctor and nurses who perform the procedure, as well as friends or family (such as the husband or boyfriend) who cooperate in a direct fashion, such as paying for the abortion or driving to the clinic.

Canon 1323, however, stipulates that no one can be excommunicated who:

Has not turned 17;

Was, without fault, ignorant of violating the law;

Acted under physical force, or under a chance occurrence that could not be foreseen or avoided;

Acted under compulsion of grave fear;

Lacked the use of reason.

Hence a woman who did not realize that an abortion triggers automatic excommunication is not subject to the penalty (unlike Anglo-Saxon civil law, in canon law ignorance of the law is an excuse). Similarly, a woman who was compelled into an abortion by an abusive husband, or a woman with Down syndrome who did not understand the nature of the act, is not subject to excommunication.

Johnstone said that determinations in specific cases can only be made under the guidance of a priest-confessor.

According to Canon 1331, an excommunicated person cannot have any ministerial part in the celebration of the Eucharist or other ceremonies of public worship; cannot receive the sacraments; and cannot exercise any ecclesiastical offices, functions, or acts of governance.

Canon 1355 gives the local bishop power to cancel a latae sententiae excommunication, usually in the context of confession: Many bishops grant all priests under their power permission to absolve from such an excommunication without getting the bishop's permission, at least in the case of a first abortion. Canon 1357 allows a priest to lift the excommunication even without such authorization if it would otherwise be difficult for the person to remain in the state of grave sin.

Canon 1041 states that anyone who has cooperated in procuring an abortion is to be barred from ordination as a priest.

It's an open question in magisterial circles whether politicians who vote for legal abortion support public funding for abortion, and/or otherwise help make abortion available, should be considered "accomplices" and hence excommunicated. Johnstone said that most moral theologians believe such votes may be morally wrong, but they do not constitute sufficiently direct involvement in an individ ual abortion to trigger excommunication.

Bishop Elio Sgreccia, vice president of the Pontifical Academy for Life and a frequent Vatican spokesman on bioethics, nevertheless told NCR in a mid-October interview that it is his "personal opinion" that politicians who support permissive abortion laws are subject to the canonical penalties for accomplices.

One exception is identified in Pope John Paul's 1995 encyclical on bioethics, Evangelium Vitae. When outlawing abortion is politically impossible, the pope held, a politician could vote for a law that permits some abortions, if it's the most restrictive result feasible and the alternative would be a more liberal standard.

"When it is not possible to overturn or completely abrogate a pro-abortion law, an elected official, whose absolute personal opposition to procured abortion was well known, could licitly support proposals aimed at limiting the harm done by such a law and at lessening its negative consequences at the level of general opinion and public morality," the pope wrote. "This does not in fact represent an illicit cooperation with an unjust law, but rather a legitimate and proper attempt to limit its evil aspects."

Cardinal Dionigi Tettamanzi of Milan, a key adviser to John Paul II on bioethical issues and a front-runner to be the next pope, defended the imposition of excommunication for abortion in his 2000 book Nuova Bioetica Cristiana.

"Excommunication for procured abortion constitutes a gesture of maternal love," Tettamanzi wrote. "It expresses and puts into action the love of Mother Church, who comes to the defense of the defenseless unborn child, and who recalls and supports the one who has erred so that it doesn't happen again."