ISRAEL'S NAVAL BLOCKADE OF GAZA IS LEGAL - AND THAT IS THE PROBLEM
In the moral dichotomy of our times, outrage has replaced reason. If a controversy involves Israel, the verdict is delivered before the facts -- Israel is presumed guilty.
Singaporeans of liberal persuasion as well as those from certain faith, jump on the bandwagon in symmpathy with pro-Palestinian mobs all over the world, raining curses on the Israeli interception of the Sumud Flottila and what they say is an illegal naval blockade by Israel. Jew-haters and empty bottles dominate social media where they really do not understand, or chose not to check, whether the blockade is lawful. Who is in the right, who is wrong, is not black and white. But of course, let's blame Israel. Let's unpack this to see if Israel's blockade of Gaza waters is legit and whether they have a right to board vessels in international waters.
The Blockade and International Law
Under the San Remo Manual on International Law Applicable to Armed Conflicts at Sea (1994), a naval blockade is legal if it is DECLARED, NOTIFIED, ENFORCED, IMPARTIAL & PROPORTIONAL.
Declaration: In June 2007, Hamas took control of Gaza. Israel tightened it's restrictions on the territory, first on land crossings, then by sea. This was part of a broader policy to isolate Hamas and prevent weapons smuggling. Initially, this was just 'restrictions'. In January 2009 Israel officially declared a de jure naval blockade. Area defined - 20 nautical miles offshore along entire Gazan coastline. The UN Palmer Report (2011) accepted that the naval blockade met formal requirements of international law.
Declaration: The Text of declaration - "The Israel Navy will enforce a maritime blockade on the Gaza Strip until further notice. The Gaza maritime area is closed to all maritime traffic.".
Compliance : Checked.
Notification: Israel sent notices to international maritime authorieis such as MSI (Maritime Safety Information system and Lloyd's List. It also shared via NOTMAR (Notice To Mariners) which is a standard naval notification method. The UN and other states were also informed.
Compliance : Checked.
Enforcement: The blockade must be effectively enforced - a blockade that cannot stop ships is not lawful. The lawfulness of a blockade depends on its effectiveness in fact, not just its declaration in law. A state cannot randomly declare a blockade. It requires naval assets (ships, aircraft, surveillance) capable of stopping vessels that try to break it. If neutral ships can freely sail through, or the enforcing navy cannot intercept, then the blockage is not credible and hence unlawful.
Compliance : Checked
Impartiality & proportionality: A blockade must treat neutral ships equally. It must apply to all foreign vessels, regardless of nationality, that try to enter the blockade zone without Israeli authorisation. It must allow humanitarian access
Israel bars bound for the Gaza coast. Palestinian fishing vessels restricted to 3-6 nautical miles off the coast. Commercial imports and humanitarian aid must pass through Israeli or Egyptian land crossings for inspection. Humanitarian Freedom Flotilla in 2010 was intercepted and diverted to Israeli port of Ashdod.
Critics say it is discriminatory. Blockade must be to deny military weapons movement, not to isolate the civilian Palestinian population of 2m. It is thus functionally discriminatory as it singles out one community (Gazan civilians) for severe restrictions that no other population faces (those in West Bank). As Egypt is involved, it is not a unilateral blockade, but a bilateral blockade which is subject to more conditions.
Israel's response is Egypt is not involved in the naval blockade. Egypt never declared its own land blockade. It merely controls its own land crossing at Rafah.
Why this matters - As the blockade-declaring state, Israel alone is accountable under international law for its enforcement at sea. Egypt's land restrictions are a sovereign border policy, governed by a different set of rules.
Compliance : Legally valid and impartial (UN Palmer Report)
Illegal, disproportionate, collective punishment (UN Human Rights Council (2010,15,21).
Israel's Naval Blockade of Gaza - Lawful By The Letter, Unsettled By Principle
Lawful by Letter - By legal standards, the blockade is technically sound - it is declared, notified, effectively enforced and impartial (on paper). These are the requirements laid down by the San Remo Manual, the post-Cold War codex governing warfare at sea.
Unsettled by Principle - Legality in form, unfortunately, does not guarantee justice in effect. The blockade traps 2 million civilians in conditions of economic paralysis amd hummanitarian fragility. Critics condemn this as collective punishment. Israel defends it as self-defence.
Both arguments are credible within their own legal logics. And this is precisely the problem. The law itself is behind the curve of the realities it now seeks to regulate. The San Remo Manual was designed for wars between states, not for asymmetric conflicts in which non-state actors like Hamas govern territory while civilians depend on external supply lines. The boundaries between combatants and non-combatants, security and punishment, legality and morality, begin to blur. In this gray zone, the blockade is both defensible legally, and uneasy in conscience.
As long as the maritime convention remains in its present state, the contradictions persist and Israel's policy is both vindicated and vilified at the same time. The world community is caught in between rules it can cite and realities it cannot yet codify.
Moving Towards A Codified Future
The conventions for naval blockade, such as the "effectiveness" rule, was born out of centuries of abuse of the blockade concept, from the "paper blockade" of the Napoleonic Wars, Berlin and Milan Decrees, Declaration of Paris (1856), London Declaration (1909) and finally codified in San Remo Manual (1994).
The Gaza blockade is more than a dispute over Israeli policy, it is a study in the limits of international law itself. Israel acts within the legality of the San Remo Manual. However, the San Remo Manual was crafted for inter-state conflicts, when applied to asymetric wars involving non-state actors, its safeguards can appear both rigid and hollow. The Gaza blockade has exposed a structural weakness in maritime warfare convention. It legitimises the practice of naval blockade which in effect can erode the humantarian principles it was meant to uphold.
Future codifications must redefine what constitutes a lawful blockade in the twenty-first century realities. It must embed and integrate considerations of proportionality, civilian dependency and asymmetric governance. Only then can international law maintain its moral authority while remain operationally relveant.
Until such time, Israel's blockade of Gaza ramains legally defensible but morally ambiguous, both a shield and a target for critique. Legal technicalities shield Israel from clear censure while civilians bear the consequences. And yes, under international law, if the blockade is legal, Israel is legally entitled to board vessels in international waters to prevent entry into the blockade zone.
Addendum (7 Oct 2025):
A friend of mine brought up San Remo rules 102 and 103 to counter the validity of the blockade.
Rule 102 : Prohibits blockades whose purpose or effect is starvation or excessive civilian harm.
Rule 103: Requires the blockading power to allow humanitarian relief.
In addition to these, there is one other rule not mentioned by my friend but which is also restrictions in the same context of what he tried to point out. This is :
Rule 100: A blockade shall not have the sole purpose of starving the civilian population or denying it other objects essential for survival.
My article is on whether the blockade passes the validity test set out in San Remo and these are covered under Rules 93-97 which I have mentioned, which concern Declaration, Notification, Enforcement and Impartiality. Israel complied with all these which legitimises the blockade and which was confirmed by the UN Palmer Report.
Rules 100, 102 and 103 does not relate to the validity, but prohibitions of the blockade. These are entirely different matters and whilst certainly Israel is challenged to defend their actions, violations do not invalidate the blockade. I think most ordinary folks lack the understanding of legalities and may be comfounded by these. There are no contradictions. I think it is important for me to clarify, thus this addendum. Let me explain with an analogy.
The Singapore Police Force sets up "roadblocks" or "checkpoints" for various purposes. This is done under Road Traffic Act s65 and Criminal Procedures Code s26. Standard operational practices follow along the lines of purpose, notification, location, enforcement, impartiality. This is akin to the way San Remo rules 93-97 legitimises blockades. It is about the process and the structure for the roadblocks and the blockade to have legal force.
Although the SPF may have the legal authority in setting up the roadblocks, it has to observe certain practices, such as it cannot be used to harass, punish, or target certain groups, must minimise risk to civilians, emergency vehicles or ambulances be allowed through, apply checks fairly, etc. All these are about conduct of the SPF at the roadblocks, similar to San Remo rules 100, 102 and 103. Any acts of misconduct does not invalidate the legal authority of the road block or blockade.
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