Why was the Eighth Amendment inserted into the Constitution?

In 1965, the US Supreme Court ruled that there was a right to privacy in the US Constitution.  In 1973, the US Supreme Court ruled on the basis of this privacy right that a woman had a right to abortion. But it also ruled that unborn children are not “persons” protected under the 14th Amendment so they have no protection against abortion, even up to birth, in some cases.  

In 1974, the Irish Supreme Court followed the US Supreme Court and identified a privacy right in the Irish Constitution, citing the 1965 US Supreme Court ruling.  It later became clear that under the Irish Constitution as it was then, the right to life of a baby in the womb was not protected: only citizenss had that protection. 

It also became clear that there was great reluctance on the part of the European Commission of Human Rights to hold that a baby in the womb was protected under the European Convention on Human Rights. 

In view of these decisions and trends, an amendment to the Constitution was needed to give babies in the womb constitutional protection for their right to life against abortion. 

If the Eighth Amendmnet were to be repealed, the protection for babies in the womb would be removed.  As Professor Gerry Whyte, a leading expert on Constitutional Law, has explained in his article in the Irish Times on 28 September 2016 (“Abortion on Demand the Legal Outcome of the Repeal of the Eighth Amendment”):

“…the most obvious interpretation of any decision to delete Article 40.3.3 is that the people will have decided to completely withdraw constitutional protection from the unborn.  In this situation, the only constitutional factor at play will be the constitutional rights of the mother and clearly these would support a much more liberal regime of abortion.”