In criminal law, iminished responsibility (or diminished capacity) is a potential defense by excuse by which defendants argue that although they broke the law, they should not be held criminally liable for doing so, as their mental functions were "diminished" or impaired. The defense's acceptance in American jurisdictions vary considerably. The majority of states have adopted it by statute or case decision, and a minority even recognise broader defenses such as 'irresistible impulse.' Some American states restrict the defence to the charge of murder only where a successful defence will result in a manslaughter conviction instead of murder. Until recently, the Republic of Ireland did not accept the partial defence. The Irish Supreme Court had rejected the existence of the defense in The People (DPP) v Joseph O' Mahony ILRM 244. The case was recently abrogated, however, by enactment of the Criminal Law (Insanity) Act 2006, effective 1 June 2006. The act, in pertinent part, specifically adopted the partial defence for the charge of murder where a successful defence will result in a manslaughter conviction instead of murder.