Related Rule
Ireland
Practice Relating to Rule 151. Individual Responsibility
Ireland’s Basic LOAC Guide (2005) provides a list of “Soldiers Rules”, one of which is: “Disobedience to the law of war is a crime and not only dishonours your country and you but renders you liable to punishment as a war criminal.” 
Ireland, Basic Guide to the Law of Armed Conflict, TP/TRG/01-2005, Director of Defence Forces Training, Department of Defence, July 2005, p. 13.
Ireland’s Geneva Conventions Act (1962), as amended in 1998, provides:
Any person, whatever his or her nationality, who, whether in or outside the State, commits or aids, abets or procures the commission by any other person of a grave breach of any of the [1949 Geneva] Conventions or [the 1977 Additional] Protocol I shall be guilty of an offence and on conviction on indictment [be liable to punishment]. 
Ireland, Geneva Conventions Act, 1962, as amended in 1998, Section 3.
The Act also provides:
Any person, whatever his nationality, who, in the State, commits, or aids, or abets or procures the commission in the State by any other person of any other minor breach of any of the [1949 Geneva] Conventions or of [the 1977 Additional] Protocol I or [the 1977 Additional] Protocol II shall be guilty of an offence.
Any person, whatever his nationality, who, outside the State, commits, or aids, or abets or procures the commission outside the State by any other person of any other minor breach of any of the [1949 Geneva] Conventions or of [the 1977 Additional] Protocol I or [the 1977 Additional] Protocol II shall be guilty of an offence.
Any person who is guilty of an offence under this section shall be liable [to punishment]. 
Ireland, Geneva Conventions Act, 1962, as amended in 1998, Section 4.
Ireland’s International Criminal Court Act (2006) states: “Any person who commits … a war crime is guilty of an offence.” 
Ireland, International Criminal Court Act, 2006, § 7(1).