Practice makes custom: a closer look at the traditional law of naval blockade.

Author:Kennedy, Ian
  1. INTRODUCTION II. WHY THE DESUETUDE OF TRADITIONAL BLOCKADE LAW MATTERS i. The Gaza Blockade ii. The Fragmentation of International Law III. THE ARGUMENT THAT TRADITIONAL BLOCKADE RULES ARE CUSTOMARY INTERNATIONAL LAW i. The London Declaration and the San Remo Manual ii. A Critical Assessment of the London Declaration iii. A Critical Assessment of the San Remo Manual IV. THE FORMATION AND MAINTENANCE OF CUSTOMARY INTERNATIONAL LAW V. STATE PRACTICE, OPINIO JURIS, AND NAVAL BLOCKADES i. State practice and opinio juris in arguments for traditional blockade law ii. State practice and opinio juris during blockades a. The World Wars b. The Chinese Civil War, 1949 c. Korean War, 1950-1953 d. Arab-Israeli War, 1967 e. India-Pakistan War 1971 f. Vietnam War, 1972 g. Arab-Israeli War, 1973 h. Iran-Iraq War 1980-1988 i. Israel-Lebanon War 2006 iii. Neutral state responses to blockades since 1945 iv. Military Manuals v. Summary of state practice and opinio juris during blockades a. State Practice b. Opinio Juris vi. Have new customary blockade laws arisen from contemporary state practice? VI CONCLUSION "Horatio: Is it a custom?

    Hamlet: ... --it is a custom/More honour'd in the breach than the observance."

    William Shakespeare, The Complete Works of William Shakespeare (London: Wordworth Editions Limited, 2007) at 676.


    In September 2011, the Turkish Foreign Minister announced that Turkey will challenge the legality of Israel's naval blockade of the Gaza Strip at the International Court of Justice. (1) The announcement followed the release of the UN Secretary-General mandated Palmer Report, which addressed the legality of the Gaza blockade. (2) Commissions created by Israel, Turkey, and the UN Human Rights Council had previously published reports that discuss the blockade's legal standing. (3)

    The four reports have all invoked what has been called the traditional law of naval blockade, which is a collection of nineteenth-century rules governing the wartime blockade of enemy coastlines. (4) The reports rely upon blockade law to different degrees, but all four assume its validity as customary international law.

    The thesis of this article is that traditional blockade law has fallen into desuetude and therefore cannot be relied upon. Blockade law has not been followed by state practice nor been understood to govern state practice for nearly a century. The desuetude of traditional blockade law does not mean that naval blockades exist in a legal vacuum; in fact they may be subject to a multiplicity of legal regimes, including the law of the sea, the law of peace (jus ad bellum), international humanitarian law (jus in hello), and international human rights law.

    This article begins by explaining why the desuetude of traditional blockade law matters. It then turns to three questions that are central to its thesis. First, what is traditional blockade law and what is the argument for its continued validity? Next, what is customary international law and how is it formed and maintained? Finally, does traditional blockade law meet the requirements of customary international law? The article concludes that traditional blockade rules have been abandoned and can no longer be considered customary international law.

    This thesis challenges the common assumption in recent literature that blockade law continues to be binding customary law. (5) The work of several influential authors supports this assumption. (6) Foremost among them is Dr. Wolff Heintschel von Heinegg, who served as a special consultant to the Israeli Commission and was cited extensively in the Palmer Report. (7) This article responds directly to some of Dr. von Heinegg's arguments.


    The relevance of the legal status of nineteenth-century rules governing coastal barricades--a tactic seldom undertaken in contemporary times--may not be self-evident. Yet this topic warrants investigation for two reasons. First, it is critical to determining the legality of the Gaza blockade. Second, it exemplifies how the problems of the fragmentation of international law can be mitigated by an examination of the relevance and validity of different legal regimes. Both points are explored below.

    i. The Gaza Blockade

    In the words of the Israeli Commission, the Gaza conflict's competing narratives sometimes seem "to present two very different perceptions of reality." (8) To avoid taking sides in this polarized arena, I will set out only the basic, uncontroverted facts of the Gaza blockade.

    In September 2007, three months after Hamas took control of the Gaza Strip, Israel declared Gaza a "hostile territory" and imposed restrictions on the passage of goods, oil, electricity and persons to and from its territory. (9) Eleven months later, in August 2008, Israel published a Notice to Mariners calling on shipping to refrain from entering the waters off of the Gaza coast. (10) This was described by Israel's Military Advocate-General as a declaration that the maritime zone of the Gaza coast was a "combat zone" or "exclusion zone." (11) Then, on 3 January 2009, during the Operation Cast Lead conflict, the Israeli Minister of Defense ordered a naval blockade off the coastline of the Gaza Strip. (12) The blockade remained in force after the conclusion of Operation Cast Lead. (13)

    Fifteen months later, in the early morning hours of 31 May 2010, Israeli Defence Forces boarded a flotilla of six vessels that was attempting to break the blockade while carrying humanitarian supplies to Gaza. (14) Nine passengers of one of the vessels, the MV Mavi Mara, were killed in the take-over. (15)

    This incident triggered the aforementioned four inquiries into the events of 31 May 2010 and the Gaza blockade more generally. On 27 September 2010, a fact-finding mission of the UN Human Rights Council ("HRC") released a report on the incident, based on over 100 interviews with witnesses. (16) It concluded that the blockade was unlawful. (17) This was followed by reports commissioned by the governments of Israel and Turkey, in January and February 2011, which concluded that the blockade was legal and illegal, respectively. In September 2011, a four-person Panel of Inquiry established by the UN Secretary-General released the Palmer Report, named for its chair, Sir. Geoffrey Palmer. It concluded that the blockade was legal, but that Israel's use of force on 31 May 2010 was excessive and unreasonable. (18) All four reports relied, to varying degrees, on the traditional law of blockade. The thesis of this article--that this legal regime is in desuetude--challenges their use of this legal regime and any conclusions that rest on it.

    ii. The Fragmentation of International Law

    In the absence of a general legislative body, the proliferation of treaties and other forms of international law has resulted in overlap among specialized fields of legal practice. This phenomenon is known as the fragmentation of international law. Among the consequences of fragmentation, in the words of the International Law Commission's ("ILC") report on the subject, is "the loss of an overall perspective on the law." (19) The four blockade reports demonstrate two problems that arise from this loss of perspective.

    The first problem is that adjudicators are likely to allocate more attention and analysis to some legal regimes than to others. This can manifest out of a scarcity of resources--the analysis must be divided between regimes, with some inevitably being crowded out. "Cherry-picking" legal regimes may also be a tactical move by the parties, or even the decision-makers, especially when different regimes point to different outcomes.

    The reports on the Gaza blockade exemplify this. The HRC Report dedicates one sentence to the traditional rules of naval blockades and three pages to humanitarian law. (20) By contrast, the Israeli Commission is far more interested in traditional blockade law. As Martin Fink writes,

    Clearly the [Israeli] Commission takes the traditional law [of blockade] as its central point of departure. It also considers humanitarian aspects to the law of naval blockade, but only as far as the provisions ... [are] mentioned in the [San Remo Manual on International Law Applicable to Armed Conflicts at Sea]. Although it briefly considers the application of human rights, it is however reluctant to view the law of blockade from a wholly humanitarian perspective that reflects the complete scope of humanitarian law. (21) These two paths of legal reasoning lead the reports to different conclusions: as noted above, the HRC Report found the blockade was unlawful, while the Israeli Commission found that it was legally sound.

    A second problem arising from competing legal regimes has to do with fact-selection. The facts that will be relevant for one regime may not be relevant for another. There is a risk that an adjudicator will allow only the facts that are relevant to one regime. Even if the adjudicator goes on to consider the second legal regime, important facts may have already been excluded, resulting in a second analysis that is superficial or incomplete. Imagine that a person is confined to a house with a front door and a back window. Food entering the house through either entrance is restricted. Two legal regimes govern the house: the first prohibits the starvation of the confined person, while the second prohibits improper window restrictions. Under the first legal regime, it would be artificial to consider the window without paying consideration to the door. Under the second regime, however, the door is of no importance at all: only the window matters to the law about windows.

    Assume that the judge deciding the case allows only facts relating to the window. She finds no violation of the law against improper window restrictions. She then turns to the law against starvation, and concludes that the window restrictions cannot be said to be illegal because its effects are...

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