The conduct of a nation's foreign relations may be affected to a considerable extent by its internal governmental organization. Generally speaking, a more energetic and effective foreign policy is possible for a nation whose government is characterized by unity and coherence. This is true not only with reference to the relations between the -departments of the central government, but also with reference to the relations between the central government and the local or state governments. In countries whose government is based on the federal plan, therefore, an important question to be considered is that as to the extent, if any, of the control over foreign relations to be assigned to the component governmental subdivisions. The tendency in federal, and even in confederate, governments is to restrict within very narrow limits, if not absolutely to prohibit, any direct control by the componernt states over foreign relations.
John M. Matthews,
States and Foreign Relations,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol19/iss7/2