Indeed, states possess the freedom to make decisions within their territorial jurisdiction, which is a direct consequence of their sovereignty. Nonetheless, there are various reasons why States might choose to abstain from certain actions within their jurisdictional boundaries, when dealing with neighbouring states, opting instead to consult, notify, or consider the opinions of their neighbours on matters to be determined. Historically, those situations are empirically related to watercourses, water resources, waterways, or watersheds neighbouring distinct territorial jurisdictions.
In his groundbreaking book, “Prior Consultation in International Law: A Study of State Practice,” Frederic L. Kirgis Jr. adeptly captures the crucial importance of States’ decision-making processes, emphasizing the need for due consideration of other States’ interests when unilateral decisions by States, even within the limits of their territorial jurisdiction, involve actual or potential “externalities” that could be rather detrimental to not only one country but the whole planet:
Negotiation is said to have substantive effects when it leads the parties to a dispute to a result in which that dispute is terminated by an agreement. On the other pole, negotiation yield instrumental effects when it heads the parties to a point where they may find a solution, being that point, overall, an agreement on arbitration or judicial adjudication.
An interesting example of instrumental effect of negotiation can be seen in the Essequibo Agreement between the the Great Britain and Venezuela
