It is an essential ingredient of sovereignty that every State has an absolute jurisdiction to determine the laws that apply within its territory and to determine, by its laws, the organ of the State that has the competence to make laws and the procedures to be followed. The competent organ that makes municipal law (the legislature) is usually different from the organ that makes international law (the executive). As a result, and following the dictates of separation of powers, while the executive is competent to enter into treaties, its competence is eroded by the competence of the legislature when a treaty is intended to be applied to municipal subjects; such a treaty intrudes into the competence of the legislature. When this occurs, the municipal applicability of the treaty would turn on the requirements specified by municipal law. This is the function of section 12(1) of the 1999 Constitution (as amended). This section bars the executive from transforming its treaty-making power into legislative powers by requiring legislative approval for the application of a treaty in Nigeria. Expectedly, the section has been variously interpreted and applied by Nigerian courts. This paper examines the views expressed by the Supreme Court in JFS v. Brawal Line Ltd and argues that the Supreme Court failed to give proper expression to the dualist nature of that section.

每个国家都有绝对的管辖权来决定在其领土内适用的法律，并通过其法律确定有权制定法律和应遵循的程序的国家机关，这是主权的基本组成部分。制定市政法的主管机关（立法机关）通常与制定国际法的机关（行政机关）不同。结果，在三权分立的指示下，行政人员有权签署条约，而当打算将条约适用于市政主体时，立法机构的权力会侵蚀其权限；这样的条约侵犯了立法机关的权限。发生这种情况时，该条约的市政适用性将取决于市政法律规定的要求。这是《 1999年宪法》（经修订）第12（1）条的功能。本节禁止行政机关通过要求立法批准在尼日利亚实施条约而将其条约制定权转变为立法权。预期该节将被尼日利亚法院进行各种解释和适用。本文考察了最高法院在JFS诉Brawal Line Ltd案，并辩称最高法院未能对该部分的二元性作出恰当的表述。