The conduct of foreign affairs pertains exclusively to the Realm.
The Lands may make treaties with foreign States on matters which fall within their own legislative competence; such treaties require the consent of the Realm.
Agreements with foreign States concerning alteration of the national frontiers shall be concluded by the Realm after the Land affected has given its consent. Frontier alterations can be effected by act of the Realm only, except in mere rectifications of frontiers in uninhabited districts.
The Realm shall take the necessary measures and make the necessary arrangements, in agreement with the Lands affected, to safeguard such interests of those Lands as may be involved in their peculiar economic connections with or in their geographical contiguity to foreign States.
Article 79.
National defence is an affair of the Realm. An act of the Realm shall uniformly regulate the military constitution of the German people, with due regard for local conditions.
Colonial affairs pertain exclusively to the Realm.
Article 81.
All German merchant vessels constitute a united mercantile marine.