Israel’s seizure of the Gaza-bound flotilla: applicable laws and legality

Editorial Introduction:

On June 4, 2010, CBC News created a FAQs (Frequently Asked Questions) page on its website on the recent high seas intervention by Israel against ships bound for Gaza with humanitarian cargo: see “Flotilla raid: FAQs on the ships trying to reach Gaza.”  Osgoode Professor (and Editor-in-Chief) Craig Scott was asked to supply summary answers for the FAQ to two questions on the legal dimensions of the incident.  What follows are more fulsome answers to each of the two questions.

CBC has linked from the shorter answers on the site to the present page, for those CBC readers who wish to delve a bit deeper.  In turn, in an exercise of Editor-in-Chief executive discretion, this page has been created as a posting on as a somewhat symbolic gesture: in the absence of a functioning international court system that would help answer the legal issues at stake in this case, the court of juridical opinion will likely be the best we will do.  To that end, it is hoped that readers of will welcome this posting on a matter outside the usual scope of postings on

Links to other online legal views are provided at the end of this


First question: What laws apply in the military seizure of a vessel in international waters?

At the most general, the applicable law is ‘public international law’ (PIL), which is the term for the law that primarily deals with interstate relations.  Within PIL, the issue of military seizure of a vessel in international waters lies at the interface of two fields of PIL, the ‘law of the sea’ and the ‘law of armed conflict.’   In both areas, both treaties (e.g. the 1982 United Nations Convention on the Law of the Sea or the 1949 Geneva Conventions on the Laws of War) and unwritten ‘customary international law’ (or, custom) may be relevant to the rules that apply to a specific incident or dispute.  Sometimes, a legal instrument will not in and of itself apply to all states, but will form the basis for states to consider custom has arisen; this is the case, for example, with respect to the classical law of naval blockades as set out in a document called the London Declaration of 1909.

Within the law relating to armed conflict, there is a standard distinction between how a state or other actors may conduct themselves once an armed conflict has started and the rules governing whether armed force can be used by a state that either initiates an armed conflict or responds to another actor’s initiation of such a conflict.  The former sub-field generally bears one of two labels, both meaning the same thing, namely, the ‘laws of war’ or ‘international humanitarian law;’ within that body of law, there is an even more specific body of law known as the law of naval blockade.  The latter sub-field (on initiation of conflict or response to such initiation) is usually be referred to as the ‘law on the use of force’, within which there is also a more specific body of law known as the ‘law of self-defence.’   Latin terms inherited form previous eras of PIL speak also of the distinction between jus in bello (roughly, the law in war) as distinguished from jus ad bellum (the law of going to war).  Israel’s justifications appear to intermingle both the jus in bello law of naval blockades and the jus ad bellum law of self-defence.

In contemporary PIL, two other bodies of law are relevant beyond the law of the sea and the law of armed conflict.  One is the law of the United Nations Charter, specifically the rules of the Charter that permit the UN Security Council to make law that is binding on all states as long as the matter falls within the broad subject matter of international peace and security; as a general matter, UN Security Council law can either modify or override rules that would otherwise be applicable.  The other area of law is what is known as ‘international human rights law’ (including a sub-set of principles around the right to self-determination), an ever-growing body of law that is now widely accepted as not only applying during armed conflicts (not only in peacetime) but as sometimes going beyond or sometimes interpretively influencing the ‘international humanitarian law’ (recall: the rules of conduct once an armed conflict is underway).

As well, apart from treaties and custom, PIL also recognizes a category called ‘general principles of law’, which arguably is relevant by helping provide content for requirements of proportionality and necessity within the law that deals with excessive use of force whether as jus in bello or jus ad bellum.

Finally, national law will also come into play in a variety of ways.  For example, any jurisdiction Israel asserts over foreign ships on the high seas needs to be authorized by Israeli law itself.  For another example, it is Turkish national law that conferred nationality on some or all of the ships in the flotilla, with this conferral then having implications for Turkey’s rights as a state under PIL with respect to vessels flying its flag.

Question 2: Was the May 31 seizure legal?

As with many areas of law, especially public international law, there can be reasonable differences of views both on exactly what legal rules apply and, once that is determined, whether the facts reveal a violation of one or more rules.  What follows is the author’s assessment of what appears to the author to be the most sustainable view, based on a combination of independent legal analysis and the dominant understanding of the applicable law within the international legal community.  The bottom-line is that the boarding and seizure do not appear to have been legal while more facts are needed in order to know whether specific acts of force by Israeli commandos were also illegal.

The Law of the Sea:

Both treaty and customary international law preclude any state from boarding and arresting – far less, attacking – a ship that has another state’s nationality on the high seas (which are those international waters beyond 12 nautical miles from any state’s coast).  There are a very few limited exceptions, such as the right of any state to accost, board, arrest and take to port a pirate ship or a slave-trading ship.  No exceptions are relevant here in the case of the Gaza-flotilla seizure.

It may be noted that a few states, notably the US, have over the years tried to assert some undefined right to seize ships on the high seas in order to arrest suspected terrorists.  Most states do not accept such an exception exists. In any case, even if such an exception exists, there is no plausible case that the persons on board the flotilla ships were, in law, terrorists.

Israel’s action thus violated the law of the sea unless it can successfully plead an exception under the laws of armed conflict.

The Laws of War / International Humanitarian Law:

Most would accept that an international armed conflict continues between Israel and Gaza (and/or the Hamas authorities in Gaza), notwithstanding Israel no longer physically occupying the Gaza strip.  More specifically, Israel claims to be enforcing a naval blockade which is a method of warfare that assumes an ongoing armed conflict.

Various treaty and, likely, customary rules do permit naval blockades by one belligerent (here, Israel) as a method to prevent neutral ships (here, Turkish) from supplying war-related material to another belligerent (here, Gaza/Hamas) and, at least according to traditional law on naval blockades, as a method of more general economic coercion.  By the classical rules, the blockade must be publicly announced and the line past which a blockade will be enforced must be precise and clear; further, for various reasons, the classical rules also require the blockade actually be effective (i.e. not just pronounced but enforced); finally, it must be applied impartially, that is, to all neutrals’ ships as opposed only to the ships of some states. However, even under traditional laws of war (untouched by contemporary international human rights law), a “principle of humanity” applies to naval blockades such that supplies intended as humanitarian aid for the populace cannot be prevented from reaching the other belligerent if one of two conditions are met: : if the blockade has (or comes to have) the purpose of starving the civilian population or denying it other objects essential for its survival; or if the damage to the civilian population is, or may be expected to be, excessive in relation to the concrete and direct military advantage anticipated from the blockade.  International human rights law almost certainly deepens the principle of humanity, for example, by influencing how to interpret the notions of “objects essential for survival” or “damage to the civilian population” that is “excessive.”

Assuming the existence of an international armed conflict here, Israel does have the presumptive power to establish a blockade that operates in conformity with the law.  However, should it turn out that the blockade is, for one or more reasons, unlawful, then the general principle would be that there can be no right to enforce an unlawful blockade – at least as long as the unlawfulness is of the sort that would be termed fundamental or a manifest breach of the law.

Notwithstanding that the law allows a naval blockade, the dominant legal view would seem to be that the blockade as a whole had become illegal well before the Gaza flotilla incident – and may indeed have been illegal virtually from the outset, three years ago, depending on its intent.  This illegality stems from reasons related to both the principle of humanity within the laws of war and that principle’s interaction with contemporary international human rights law such as with respect to the rights to food, shelter, health, and, more generally security of the person.

Justice Richard Goldstone and his colleagues on a commission of inquiry established by the UN Human Rights Council after the 2008-09 land conflict between Israel and Gaza take the view that both in intent and in effect the Israeli blockade – land and sea, combined – is actually operating as a form of collective punishment or reprisal against the population at large.  This is due to a combination of factors, including: evidence as to intent of Israel decision makers, evidence that quantities of humanitarian supplies that Israel permits into Gaza are grossly inadequate to the imperative of humanitarian relief, and evidence that many materials that should be permitted to enter (e.g. concrete) are in fact barred.

Further, UN Security Council Resolution 1860 of January 8, 2009 (during Israel’s incursion into Gaza in response to rocket fire from Gaza) contains provisions that come close to calling for the blockade to be lifted or at the very least implemented in a way that meets humanitarian obligations.  In Resolution 1860, the Security Council (which, it must be noted, includes Israel’s stalwart ally, the US) “[c]alls for the unimpeded provision and distribution throughout Gaza of humanitarian assistance, including of food, fuel and medical treatment”, “[w]elcomes the initiatives aimed at creating and opening humanitarian corridors and other mechanisms for the sustained delivery of humanitarian aid”, and “[c]alls on Member States to support international efforts to alleviate the humanitarian and economic situation in Gaza.”  The reader should bear in mind that the failure of the Council to specifically declare the blockade illegal or to call for it to be lifted has to be read against the need to achieve the assent of the US for any resolution to be adopted.  A broader analysis of the opinion of member states of the UN could well reveal that the large majority do take the view, with Justice Goldstone, that the blockade is illegal.

It is also worth noting that, after the seizure, the Security Council agreed on June 1 on what is known as a Presidential Statement (a step below a formal resolution).  The President stated on behalf of the entire Council that “it reiterates its grave concern at the humanitarian situation in Gaza and stresses the need for sustained and regular flow of goods and people to Gaza as well as unimpeded provision and distribution of humanitarian assistance throughout Gaza.”  It also called on Israel to permit all the ships’ goods to proceed to Gaza, although it did not say that this must occur by way of allowing the ships themselves to.  Again, the United States’ views had to be taken into account in crafting this Security Council statement.

There is also a more technical but still fundamental reason why the blockade has been illegal in its operation, a reason that also shows why the specific exercise of the blockade in the specific case of the Gaza flotilla was illegal (even if one refuses to accept the view that the blockade is illegal by virtue of excessive harm to the populace). Where a blockade is lawful, a blockading state still has the right to require a neutral ship to allow itself to be inspected in order to make sure that the cargo is indeed humanitarian and does not also include, for example, armaments.  But, significantly, traditional laws of war long ago evolved to the point of recognizing the obligation of the blockading state to inspect cargo under the supervision of a neutral party, such as the International Committee of the Red Cross, in order to make sure humanitarian supplies are not seized or diverted from their intended destination.

Especially when overlain with evidence that Israel’s categories of humanitarian relief supplies are narrower than warranted and also in light of allegations that Israel has at times failed to send on supplies by land that it has said it would send after inspection, the failure of Israel to create a system of third party supervision arguably vitiates the entire blockade scheme.  The specific failure to involve third party inspectors in the case of the Gaza flotilla, combined with there being no transparency as to what supplies will or will not eventually make their way to Gaza (because the boats are not permitted to continue to port in Gaza and have been seized), means that the boarding and seizure in this case was also an illegal implementation of the law of blockade.

The Law of Self-Defence

Israel often does not distinguish whether it is employing the blockade as a method within the laws of war in the context of an ongoing conflict or whether it views the blockade and the right to board and seize ships as part of the law of self-defence in response to threats of force (with, on this view, there being no need to find an underlying armed conflict to be underway).  There are legal complexities involved in the melding of these two areas of law, but the better view is that the matter needs to be looked at as a matter of the methods of warfare within an ongoing armed conflict and not as the right to use force outside of a prior armed conflict. In any case, there is almost no support amongst states or scholars outside the US or Israel for viewing facts such as these as being sufficient to generate a right of self-defence.  Israel’s action would fall into the extreme end of the spectrum of the kind of preventative use of force that international law does not accept.  International law instead requires that any threat be both clear and imminent before force can be used to take anticipatory action.

Degree of Force in Implementation of the Blockade

Principles of necessity and proportionality are relevant to the actual conduct of the operation to interdict the Gaza flotilla, whether one applies these principles as rules within the laws of war dealing with taking military measures against civilian actors, as constraints within the law of self-defence, or as principles that both international human rights law and general principles of law bring to bear on the situation.

On this point, more clarity as to the facts and reflection, as those facts clarify, are still needed.  However, a framing question must surely be: does boarding civilian ships i(that have announced the intention of delivering humanitarian aid) in darkness, by use of helicopter-delivered commandos, and so far away from the Gaza coast (and, it seems, four times as far out to sea as the normal blockade line of 20 miles from Gaza) contravene principles of necessity and proportionality that permeate contemporary international law?  If the answer to this question is negative, then the method of seizure also violates international law, whether or not the blockade as whole or the blockade in its general operation is legal.

A word of caution is required here. None of this denies that the individual Israeli soldiers had the right to defend themselves if, as appears from some video, they were met by what seems a vicious use of weapons, such as metal bars, shown by Israeli video. The soldiers’ specific use of force may turn out to have been excessive, but no one has all the facts at hand to know this yet. However, we should not let the issue of the justification of the lethal force during shipboard operations obscure the prior question of whether Israel’s decision makers lawfully placed its own soldiers in this situation in the first place.

Nor does any of this go to whether those on board may also have had a right to personal defence or defence of the ship, depending on their perceptions of their own physical danger and taking into account the background of believed illegality of the blockade. As with the lethal use of guns by Israeli soldiers, all the facts will need to be clarified to know whether the resistors themselves used excessive force (as, I must say again, Israeli video certainly suggests was the case, in at least some situations where we see a group  clubbing one or more downed soldiers).


For those interested in other online contributions on the legality questions with respect to the Gaza-flotilla events, you may want also to read “Israel’s naval blockade pitches and rolls with the Law of the Sea” by Ed Morgan (Professor of Law, University of Toronto), “They shouldn’t have been there: Israel’s soldiers may have acted in self-defence, but boarding a flotilla of aid ships on the high seas violated international law“, by Michael Byers (Canada Research Chair, University of British Columbia), “Gaza fleet raid raises questions over legality of Israel’s blockade” by Douglas Guilfoyle (Lecturer in Law, University College, University of London), and “Legal Issues Raised by Israel’s Blockade of Gaza” by Dapo Akande (University Lecturer in Public International Law, University of Oxford) including comments by Bruce Broomhall (Professor of Law, Université du Québec à Montréal).

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