One of the many Latin terms of art used in law, ex aequo et bono translates as “what is just and good.” In legal use, it refers to a type of case that is decided based on justice in the given circumstances, rather according the codified law or precedent. Ex aequo et bono is sometimes used in matters of arbitration or in international law where legal codes may be ill-defined or contradictory.
Ex aequo et bono is based on the idea that a legal system is meant to be comprehensive, even if laws do not always specify every possible circumstance. Since judges are appointed to make make decisions based on justice, they can be empowered to rule in situations where laws are vague, contradictory, or even non-existent. It is important to note that not all legal systems allow this practice, and even in those that do have provisions for ex aequo et bono, its use is extremely rare.
International law is a murky area of judicial practice. If country A has labor laws that prohibit workers from working more than 12 hours a day, and country B allows up to 16 hours a day, international businesses must reconcile these differing standards in order to do business in both countries. This is a circumstance in which ex aequo et bono might be applied to a lawsuit, since the judge cannot necessarily decide that one country's law should take precedence. Instead, the judgment could be based on what is just and good given the specific circumstances. In guidelines laid out by the United Nations Commission on International Trade Law, and the International Court of Justice, ex aequo et bono can only be used when all involved parties agree.
Ex aequo et bono may be used informally in some forms of law. In divorce arbitration, for instance, couples may agree to settlements, custody division, and debt assignment based on an equitable agreement, rather than on codified law. In many regions, even if specific division laws do exist, divorcing couples are offered the option to craft their own settlements, or do so with the help of an arbitrator or moderator. If a judge suspects coercion or believes the settlement is patently unfair to one of the parties, he or she usually has the ability to reject it and abide by the specific laws instead.
The greatest concern with the application of ex aequo et bono is the threat to judicial objectivity. The concept truly dates back to the days when ruling monarchs served as judges, leading to unending examples of subjectivity and corruption. Some critics suggest that use of the concept directly conflicts with the stated role of the judge, which is to impose and interpret written law. In light of these concerns, this method of judgment is used rarely, and even banned outright in some jurisdictions.