Rule of Necessity Law and Legal Definition

Rule of necessity is a common-law rule, under which a judge, even though s/he has an interest in the case, has a duty to hear and decide the case if it cannot otherwise be heard. In short, this rule allows a judge or other official to hear a case, despite bias or conflict of interest, when disqualification would result in the lack of any competent court or tribunal. This is necessary as otherwise some litigants may be denied their right to a forum or resolution of the crucial matter.