The roots of many words and phrases used in legal systems throughout the world can be traced back to the ancient Roman legal system from which many modern-day legal systems sprang. The term "ad litem" in one such phrase. The literal translation of ad litem is "for the purpose of the legal action only." It is typically used to describe someone who has been appointed by a court to look after the interests of a person, or an estate, throughout the pendency of a specific legal action only.
In the United States, a guardian ad litem generally refers to a person who is appointed by the court to look after the best interests of a minor, or incapacitated adult, in most cases. Other countries throughout the world have their own terminology for a guardian ad litem; for example, the Scottish equivalent is a "curator ad litem." The role of a guardian ad litem is to be the voice for someone involved in litigation that is too young or is incapable of speaking for himself or herself. The guardian is often an attorney, but is not required to be.
In a divorce proceeding, or custody case, a minor child is often the subject of the lawsuit, yet is incapable of speaking for herself or himself in court due to his or her age. As a result, a judge will frequently appoint a guardian ad litem to be his or her voice. The guardian does not consider the interests of either parent, only those of the child involved in the case.
Guardianship proceedings are another example of when a judge may appoint a guardian ad litem. When a guardianship petition is filed with a court, the ward, or person who allegedly needs a guardian, may not be able to speak for himself or herself due to a physical or mental incapacity. For this reason, a judge may appoint a guardian to look after his or her legal interests during the case.
Occasionally, a court will also appoint a guardian ad litem in a probate proceeding. Probate is the legal procedure whereby a decedent's estate is inventoried, creditor's paid, and assets passed down to the beneficiaries. If the appointed representative is unable, or unwilling, to carry out his or her duties with regard to the estate, then a court may appoint an estate guardian to make sure the estate proceedings are handled appropriately.