Non liquet

In law, a non liquet is a situation where there is no applicable law. Non liquet translates into English from Latin as "it is not clear." According to Cicero, the term was applied during the Roman Republic to a verdict of "not proven" where the guilt or innocence of the accused was "not clear." Lacuna is a related word which means "gap, void, defect, want, or loss" and is used to indicate a gap in the law. Lacunae are distinct from loopholes, in which a law exists but which can be circumvented legally due to an unforeseen or unintended inadequacy in the said law. A lacuna, on the other hand, is a situation in which a law or provision is lacking in the first place.

That is to say, a court comes to the conclusion that the situation engaged in a case has no answer from the governing system of law. This is of particular relevance to international law since international courts, be it the International Court of Justice or ad hoc tribunals, cannot invent law to redress a lacuna. As has now become the practice, the last resort that can be taken recourse to in deciding contentious cases is the widely accepted law of civilized nations (see generally Barcelona Traction, as accepting the doctrine of estoppel as part of international law). The ex aequo et bono jurisdiction has to date never been accepted by states, and it is believed that states would never accept it. Thus, absence of determinable international law leads to the court declaring something non liquet. But it has been argued by many that invoking of the non liquet doctrine is opposed to the notion of law being a complete (and autonomous) system. Note that municipal courts enforcing international law are not constrained to declare an area non liquet.

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