In the Republic of Ireland the government has proposed amending the Irish Constitution in order to improve children's rights. In this article I will argue that the proposed amendment represents a serious diminution in the rights historically afforded to young people who offend, disregards Ireland's commitments under international law and also ignores the well established link between child maltreatment and youth offending. The Irish approach echoes developments in the English youth justice system where the welfare concerns of young people who offend have become marginalised. I will compare the Irish and English approaches with the Scottish youth justice system which looks beyond young people's offending behaviour and provides a multi-disciplinary assessment of the young person's welfare needs. I will conclude that in Ireland, and in England, the best interest principle must be applied fully, without any distinction and integrated in all law relevant to children including laws regulating anti-social and offending behaviour.