Neutrality in International Law

From the Sixteenth Century to 1945

Kentaro Wani

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781351978545
• Edition: 1
• Topic: Law
• Subtopic: International Law
• Index: Law

Neutrality is a legal relationship between a belligerent State and a State not participating in a war, namely a neutral State. The law of neutrality is a body of rules and principles that regulates the legal relations of neutrality. The law of neutrality obliges neutral States to treat all belligerent States impartially and to abstain from providing military and other assistance to belligerents. The law of neutrality is a branch of international law that developed in the nineteenth century, when international law allowed unlimited freedom of sovereign States to resort to war. Thus, there has been much debate as to whether such a branch of law remains valid in modern international law, which generally prohibits war and the use of force by States.

While there has been much debate regarding the current status of neutrality in modern international law, there is a general agreement among scholars as to the basic features of the traditional law of neutrality. Wani challenges the conventional understanding of the traditional neutrality by re-examining the historical development of the law of neutrality from the sixteenth century to 1945. The modification of the conventional understanding will provide a fundamentally new framework for discussing the current status of neutrality in modern international law.

1 Origins of the concept of neutrality

Neutrality from the sixteenth to eighteenth centuries

As stated in the Introduction, some scholars such as Grewe, Miele and Oeter have pointed out the fact that treaties called “neutrality treaties” were concluded between States in Europe from the sixteenth to eighteenth centuries, and in State practice during this period, the status of neutrality was not a status automatically established as a result of the outbreak of war: rather, it was a status contractually and individually created by a neutrality treaty concluded between a belligerent and a third State, i.e. a State not participating in the war. The studies by these scholars should be highly regarded for focusing on neutrality treaties, which have been overlooked by most other scholars, and for identifying the significance of such treaties in the historical development of the law of neutrality.¹

However, there are some inadequacies in those studies by Grewe, Miele and Oeter.

First, there are differences of opinions among them as to the content and legal character of a neutrality treaty, or in other words, as to what legal relation was established by a neutrality treaty. To state in advance the conclusion of section 1 of this chapter, a neutrality treaty was a treaty in which a contracting State not participating in a war promised not to assist the enemy of the other contracting State, and the latter contracting State promised not to involve the former State in the war. This conclusion is the same as that held by Miele. In contrast, Grewe only focuses on the fact that, in a neutrality treaty, a contracting State not participating in a war promised not to assist the enemy of the other contracting State, and he overlooks the fact that the latter contracting State promised not to involve the former contracting State in a war.² In view of these differences of opinions among scholars, we need to reconsider the provisions of neutrality treaties and to clarify the character of such treaties. Section 1 of this chapter will discuss these points.

Second, Grewe, Miele and Oeter have not identified the theoretical basis of the theory of neutrality as presented by eighteenth-century scholars. According to them, while a neutrality treaty concluded between a belligerent and a third State had been considered as a precondition for the legal status of neutrality in State practice between the sixteenth and the eighteenth centuries, eighteenth-century scholars institutionalised the conception of neutrality (“eine rechtliche Institutionalisierung” of the conception of neutrality³), in that the legal status of neutrality became to be established without concluding neutrality treaties. As there are differences of opinions among scholars regarding the character of neutrality treaties, it is quite natural that there are also differences of opinions regarding the nature of the theory of neutrality presented by eighteenth-century scholars, which institutionalised the conception of neutrality on the basis of the practice of neutrality treaties. However, Miele, who came to the same conclusion as taken by this book with regard to the character of neutrality treaties, has not clarified how the conception of neutrality could be institutionalised. In other words, a neutrality treaty was an agreement between a belligerent and a third State by which the former promised not to involve the latter in a war. Miele has not clarified why belligerent States should not involve a third State in a war when such an agreement does not exist. Section 2 of this chapter considers the theory of neutrality as presented by eighteenth-century writers, especially its theoretical basis.

Section 3 will consider the issue of third States’ maritime commerce with belligerents in wartime (the so-called “neutral commerce”), which has been emphasised in descriptions of the historical development of the law of neutrality in existing studies, and its relationship with the conception of neutrality as clarified in sections 1 and 2 of this chapter.

1 Neutrality treaties: neutrality in State practice from the sixteenth to eighteenth centuries

1.1 Origins of the concept of neutrality in international law

The Latin word neutralitas, which is the basis of words meaning neutrality in several European languages (neutrality, Neutralität, neutralité, neutralità, etc.), was formed in the Middle Ages from the Classical Latin word neuter. Neuter is an adjective that corresponds to the English word “neither” and the word neutralis, meaning a “neutral State”, as well as the word neutralitas, meaning the status of neutrality, were established on the basis of the word neuter. Although the word neuter appears in dictionaries of Classical Latin, the words neutralitas and neutralis did not exist in Classical Latin and only appeared in the Middle Ages as Vulgar Latin.⁴

The process how the words neutralitas and neutralis derived from the word neuter is explained by Christian Wolff (1679–1754):

In war those are called middle parties (In bello Medii) who are attached to neither belligerent party (neutri belligerantium parti adhærent), consequently do not involve themselves in the war. They are commonly called neutrals (Neutrales) because, for the purpose of the war, they favour neither party (neutri parti belli causa favent), and the condition of the nations which follow neither of the belligerent parties in war is called neutrality (Neutralitas), and their lands are called neutral lands (Terræ neutræ).⁵

The word neutralis is used because these States support neither (neuter) of the belligerents as allies, and its status is referred to as neutralitas. The word neutralitas, which had at first been used as a medical term,⁶ came to be used as a concept of international law in the sixteenth century in treaties called “neutrality treaties” (pacta neutralitatis; traités de neutralité). Within the range of available primary historical resources, the oldest neutrality treaty is a neutrality treaty concluded between Burgundy and France in 1522,⁷ and many neutrality treaties were concluded until the eighteenth century.

The chronological order of published neutrality treaties as found in Du Mont’s Corps universels du droits des gens and Parry’s Consolidated Treaty Series is as follows: (1) the neutrality treaty between Burgundy and France (8 July 1522),⁸ (2) the treaty between France, Spain and the Swiss Confederation regarding the neutrality of Burgundy (22 September 1595),⁹ (3) the letters of neutrality accorded to Lorraine by France (19 June 1596),¹⁰ (4) the neutrality treaty between Sweden and the Catholic German States (29 January 1632),¹¹ (5) the neutrality treaty between Trier and Sweden (12 April 1632),¹² (6) the neutrality treaty between France and Tuscany (11 May 1646),¹³ (7) the neutrality treaty between Mainz and France (9 May 1647),¹⁴ (8) the neutrality treaty between Sweden and Courland (4 June 1647),¹⁵ (9) the neutrality treaty between France and Mantua (9 July 1658),¹⁶ (10) the neutrality treaty between Denmark, Brandenburg, Münster, and Brunswick–Lüneburg–Hannover (11(21) September 1675),¹⁷ (11) the neutrality treaty between France and Brunswick– Lüneburg (18 October 1675),¹⁸ (12) the neutrality treaty between France and the Swiss Confederation (7 May 1689),¹⁹ (13) the neutrality treaty between France and the Netherlands (24 November 1733)²⁰ and (14) the neutrality treaty between Austria–Hungary and France (1 May 1756).²¹

We will first examine the content of these treaties, that is to say, the content and character of legal relation established by a neutrality treaty between a belligerent and a third State (section 1.2), and then will consider the background to the practice of concluding neutrality treaties during this period (section 1.3).

1.2 Content of neutrality treaties

1.2.1 Reciprocal relationship between a belligerent and a third State in a neutrality treaty

A neutrality treaty is a treaty concluded during a war (or immediately before the outbreak of war) between a belligerent and a third State, in which they exchange certain promises.²² The neutrality treaty that most clearly shows the reciprocal relationship between the promise on the part of a belligerent and the promise on the part of a third State is the neutrality treaty between Sweden and the Catholic German States in 1632, which was concluded during the Thirty Years’ War. This treaty, after providing in the preamble that “the King of Sweden, in consideration of the desire of the Duke of Bavaria and the Catholic League to acquire neutrality (aiant égard au désir que le Duc de Bavieres, & la Ligue Catolique ont d’obtenir la Neutralité) … will accord the neutrality on the following conditions (accordera la Neutralité aux conditions suivants)”, and provides, as one of the “following conditions”, that Bavaria and the Catholic League shall “faithfully and sincerely observe neutrality (observeront la Neutralité inviolablement & sincerement)” (Article 7).²³ In short, in this treaty, Sweden, a belligerent in the war, promised to accord neutrality to Bavaria and the Catholic League (third States in the war) on the conditions that the latter States promised to observe neutrality in the war.

What does it mean for a third State to “observe neutrality”, and what does it mean for a belligerent State to “accord neutrality” to the third State? In other words, what were the promises made by each contracting State in a neutrality treaty? We shall answer these questions by analysing the provisions of neutrality treaties.

1.2.2 “Observe neutrality”: promise on the part of a third State in a neutrality treaty

A direct definition of the meaning of the term “observe neutrality” is not found in the provisions of neutrality treaties, but the meaning of this term can be clarified by examining the way it is used in each treaty.

Some neutrality treaties provide that a contracting State shall not assist the enemies of the other contracting State and shall, “on the contrary”, “observe neutrality”. For example, Article 7 of the 1632 neutrality treaty between Sweden and the Catholic German States, provides that the Catholic German States shall not per...