States have divided the seas orderly: what explains that?, by Rodrigo Fracalossi de Moraes

Until World War II, state control over the ocean was limited to narrow strips of sea areas (restricted by the 3-nautical mile limit norm), lines of communication and naval choke points. After the war, however, various states started to make territorial claims over large portions of the seas, unilaterally at first and later in the context of multilateral negotiations. The United States was the first country to do that, soon followed by others, especially Latin American countries in the Pacific Coast. Since then, states have been progressively extending control over the seas, having now jurisdiction over about 40% of the oceans. From a 3-nautical mile limit, states’ jurisdictions were extended to up to 12 nautical miles of territorial sea, 188 nautical miles of Exclusive Economic Zone, as well as the possibility of extending legal continental shelves. Why and how has this occurred?

The article The parting of the seas: norms, material power and state control over the ocean published in vol. 62 no. 1 of the Revista Brasileira de Política Internacional (2019) argues that states’ main interest in shifting from previous policies was to have exclusive control over natural resources, especially oil and fish stocks. With the expansion of knowledge about these resources and technological capacity to exploit them, there was a rush to control them.

Yet, the partition of sea areas was relatively peaceful, with no major wars arising from competition for resources. This is puzzling due to the enormous potential of these resources to increase the wealth and power of those controlling them. Drawing from an English School perspective, this paper argues that this was possible because states extended the norm of sovereignty to the seas. As a norm of co-existence, this contributed to keep the international system as a state-centric space and maintain a minimum level of order. Governments considered that using this norm was a good way to further states’ interests and prevent conflict. In fact, with some exceptions, states did not scramble to control sea areas: their partition occurred with only minor incidents, given the potential conflicts that might have occurred due to competition for natural riches. The perspective that this norm should govern interstate relations concerning control of sea areas was observed in both developed and developing countries, from different regions, and with different levels of material power.

This norm prevailed over at least two others. First, the norm of freedom, under which jurisdiction over large parts of the seas would not exist, and regulation of maritime areas would be weak or inexistent. This is equivalent to the Grotian proposal of a mare liberum and close to the idea of res nullius. Second, the principle that the seas are a common heritage of mankind. This is equivalent to the idea of res communis, in which focus is on redistribution of sea resources and sustainability of sea exploration.

As illustrative cases, the paper analyses the positions of the United States, Brazil and China on the current regime of the seas, concluding that interests of the United States and Brazil are aligned, and that they have strong incentives to maintain the regime. They have benefitted from it by extending sovereignty over large portions of the seas and gaining exclusive control of huge natural riches, especially oil and natural gas. China has different incentives, as it has benefitted less from this regime. Yet, it shares with the United States and Brazil the position that interstate relations concerning possession of sea area should be governed by norms, even if the current regime is perceived as imperfect.

Read the article

Moraes, Rodrigo Fracalossi de. (2019). The parting of the seas: norms, material power and state control over the ocean. Revista Brasileira de Política Internacional, 62(1), e003. Epub April 15, 2019.

About the author

Rodrigo Fracalossi de Moraes – Institute for Applied Economic Research – Ipea – Department of International Studies, Rio de Janeiro – Rio de Janeiro, Brazil (

How to cite this note

Mundorama. "States have divided the seas orderly: what explains that?, by Rodrigo Fracalossi de Moraes". Mundorama - Revista de Divulgação Científica em Relações Internacionais,. [Acessado em 26/05/2019]. Disponível em: <>.

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