Duhaime's Law Dictionary

Boni Judicis Est Ampliare Jurisdictionem Definition:

Latin: good justice is broad jurisdiction.

Related Terms: Equity

Also it is the duty of a good judge to enlarge the jurisdiction of his court.

This is a fundamental tenet of equity which almost by definition, is not to be hand-cuffed by the strict words of the common law instead, even in a vacuum of law, can and is encouraged to find jurisdiction even where none has existed before if necessary to do justice in a case.

Thomas Jefferson once wrote to an merchant, Boston sheep farmer, William C. Jarvis, in 1820:

"To consider the judges as the ultimate arbiters of all constitutional questions (is) a very dangerous doctrine indeed, and one which would place us under the despotism of an oligarchy. Our judges are as honest as other men and not more so. They have with others the same passions for party, for power, and the privilege of their corps. Their maxim is boni judicis est ampliare jurisdictionem (good justice is broad jurisdiction), and their power the more dangerous as they are in office for life and not responsible, as the other functionaries are, to the elective control. The constitution has erected no such single tribunal, knowing that to whatever hands confided, with the corruptions of time and party, its members would become despots. It has more wisely made all the departments co-equal and co-sovereign within themselves."

Herbert Broom suggests that the four word Latin maxim stands for this much longer English rendering:

"The maxim of the English law is, to amplify its remedies, and, without usurping jurisdiction, to apply its rules to the advancement of substantial justice."

He adds:

"The principle, then, upon which our courts of law act is to enforce the performance of contracts not injurious to society, and to administer justice to a party who can make that justice appear, by enlarging the legal remedy, if necessary, in order to attain the justice of the case ; for the common law of the land is the birth-right of the subject....

A maxim of Chancery - equity.

Lord Tangley called it an:

"... old medieval maxim."


  • Broom, Herbert, A Selection of Legal Maxims Classified and Illustrated, 10th Ed., (London: Sweet & Maxwell Limited, 1939)
  • Earl of Bath v Sherwin, 22 ER 206
  • Russell v. Smyth,9 M. & W. 818 per Justice Abinger
  • Tangley, Lord, International Arbitration Today International Arbitration: A Symposium, 15 ICLQ 720 (1966)

Categories & Topics:

Always looking up definitions? Save time with our search provider (modern browsers only)

If you find an error or omission in Duhaime's Law Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!