The Government's 172-page Green Paper on abortion has been recognised by both pro-choice and "pro-life" groups as a fair and substantial summary of the issues and their legal and medical context. Its very existence is a measure of how far we have come from the first abortion referendum in 1983.

Then, a well-heeled pressure group with a message of deceptive simplicity prevailed on two shortlived governments in succession to commit themselves to a constitutional amendment. Neither saw much real need for it, but each in turn was made to see a political need: if they didn't bow to the pressure, the other lot might outflank them. Besides, they didn't see that it could do much harm. But it did.

In that debate, the medical and legal voices which pointed to problems with the concept and detail of a constitutional amendment were dismissed as scaremongers. Then, eight years later, a pregnant 14-year-old rape victim was prohibited by court order from leaving Ireland for a period of nine months and from having a termination anywhere in the world. There was national and international outcry.

The State lived on tenterhooks until the Supreme Court set the order aside on a number of grounds. Even then, horror was followed by confusion. Referendums later that year (1992) copperfastened the rights to travel abroad for abortion and to give or receive information about legal abortion abroad. But a third proposal, to deal with the substantive law of abortion in Ireland, was rejected.

This week, a spokeswoman for the Pro-Life Campaign repeated their demand for a new referendum and dismissed the 1983 experience as "irrelevant". But those who refuse to learn the lessons of history are doomed to repeat them. As the Green Paper makes clear, there are plenty of pitfalls for those who would act first and think later.

The PLC, the Catholic bishops and others support "a clearly worded pro-life amendment". But such an amendment will always be a weapon which the State or a pressure group can use to seek court orders, backed by sanctions including imprisonment, against a pregnant woman or others.

The X case demonstrated this graphically, and the same potential will be present in any other amendment, in a degree which will vary with the exact wording. No amendment, accordingly, should be passed unless we as a community are prepared to see it used, with penal sanctions, against an actual person.

WE cannot insert a provision into the Constitution as a mere statement of principle. A constitution al right, once granted or acknowledged, is self-activating. Sooner or later, as the X case shows, it will be used. It transpired from the public reaction to the X case in 1992 that very few of those who had voted Yes eight years earlier could stomach the provision being coercively enforced in the way it was. In very judicious language, the Green Paper makes this point.

Judging from the Green Paper's summary of submissions received, the pro-life lobby no longer wishes to restrict the right to travel or information. It would be good to have this clearly confirmed. If this is so, it represents a major change from their previous policy which saw constant litigation from 1985 to 1992 directed at restricting abortion information.

The Green Paper discusses a number of medical conditions in which termination of pregnancy might be advised in other countries, or might occur as a result of medical treatment. These conditions, which are rare, include certain cancers, cardiac disease, ectopic pregnancy and eclampsia. In such cases, the death of the foetus is sometimes a certain or probable consequence of the treatment.

Pro-life groups and others whose approach is based on scholastic philosophy do not regard such destruction of the foetus as abortion. Using the principle of "double effect", they claim the destruction of the foetus is merely an unintended side-effect of a procedure. The intended, and therefore real, object is theraputic of the mother. Abortion in the usual sense is described by such people as "induced abortion" or "deliberate intentional abortion".

This view is based on the medieval philosophical theories associated with St Thomas Aquinas. He was concerned with the moral quality of actions and focused on intent. If my intent is to benefit the mother, the abortion is an unintended side-effect and so not wrongful. He also thought that a foetus was not "ensouled" until several months after conception and that a female foetus received its soul later than a male one.

These philosophical categories are at the heart of calls for an absolute ban on "abortion". Whatever their standing in moral philosophy, they are quite contrary to modern legal thought, which presumes that a person intends the natural and probable consequences of his or her actions. It would be virtually impossible to have a criminal law without this objective presumption, because guilt or innocence would depend wholly on subjective intent.

THE Green Paper notes that it is difficult to see how the destruction of the embryo in certain procedures can be described as "an unintended side-effect".

This fundamental difference in the sense in which different groups use the term "abortion" is a principal reason why debate on this topic is often a dialogue of the deaf. If the Green Paper ensures the same words mean the same thing throughout the discussion, that in itself will be significant progress. This is so especially because the Medical Council's ethical guidelines employ the "side-effect" phraseology.

If we are to lay down legal norms for abortion, this can only be done on the basis that natural consequences are regarded as intended consequences. If this is not done any new laws would be utterly unpredictable in effect.

The Green Paper defines and clarifies many other issues, legal and medical, and gives a good deal of pure information: a medical glossary, and a table showing the abortion provisions applicable in other EU states. The overall impression is the complexity of the issue, and of the solutions it has evoked in other countries.

The medical and moral issues are complex in themselves. The attempt to formulate a legal regime adds a complexity of a different kind. A legal formulation is not about what one personally thinks is best, or at any rate allowable: it is about what we are prepared to enforce on others, including very vulnerable people.

This paper's thorough review of the medical and legal context and its survey of options are an excellent starting point for debate. In its sober outline of the various complexities it breaks new ground: it treats the electorate as intelligent adults. The paper requires careful reading and absorbing: I cannot understand those (including the leader writer of this newspaper) who call for immediate or early legislation. We have already caused human misery and historic division by over-hasty prescriptions.

This paper provides information in very accessible form which all can read. The priority now is to seek some degree of consensus on the basis of it. Extreme positions, on both sides, are often based on false simplicities. If these can be set aside in favour of a detailed consideration of specific problems, some consensus is not impossible.

This will take time, but it seems better than a renewal of the bitter and often ill-informed divisions of 1982 to 1992.

Adrian Hardiman is a Senior Counsel