The passing of the 23rd Amendment of the Constitution is likely to have little effect on the day-to-day lives of Irish citizens - unless they become involved in serious war crime or genocide on an international scale, or harbour others doing so.
If the Irish legal system fails to act against them, they could be prosecuted and brought before a new international criminal court, to be set up when 60 states ratify a statute resolving to do this. The amendment will allow Ireland to become one of them. Already 32 states have added their signatures to the resolution.
The amendment will introduce a subsection into Article 29 of the Constitution, which deals with international obligations, stating: "The State may ratify the Rome Statute of the International Criminal Court done at Rome on the 17th day of July 1998."
These dry words describe the agreement reached by a UN conference on the establishment of a permanent international criminal court to deal with serious crimes against humanity, such as genocide, war crimes and aggression.
The statute itself defines the crimes it will deal with and sets out various technical details, including the jurisdiction of the court and the general principles of criminal law which will be applied in it. It also details the procedures for investigation, prosecution and trial, and the penalties to be imposed. It sets out the court's composition and how it will be administered.
The definition of genocide used in the statute is identical to that in the 1948 Convention on the Prevention and Punishment of Genocide. Crimes against humanity will include serious human rights violations such as murder, slavery, forcible transfer of population, unlawful imprisonment, torture, sexual violence, enforced disappearance and apartheid against the civilian population. War crimes include grave breaches of the Geneva Conventions of 1949.
The kind of work such a court will do has already been seen in the war crimes tribunals investigating crimes committed in Rwanda and the former Yugoslavia, where a number of people have been successfully prosecuted. However, these tribunals are operating on an ad-hoc basis.
The setting-up of a permanent international criminal court to investigate such crimes is seen as part of establishing international order, peace and security.
An amendment to the Constitution is necessary because sovereign power to administer criminal justice rests with the Irish courts under the Constitution, and this will involve a partial transfer of this sovereign power.
The Irish State already participates in two international courts, the European Court of Justice and the European Court of Human Rights in Strasbourg, but these did not require constitutional amendment. The former is part of the EU system of law and Ireland became part of it when it acceded to the EU. The latter was set up by the Council of Europe and oversees the implementation of the European Convention on Human Rights. Irish citizens may appeal to the court in Strasbourg since Ireland signed up to granting them that right.