The Danger of Attempting to Breach a Maritime Blockade

According to the Laws of War and the Laws of the Sea, any vessel that attempts to breach a legally imposed maritime blockade becomes a legitimate military target. The country that imposed the blockade is thus entitled, and possibly even required, to use all necessary force to prevent the intended breach. So, when Greta Thunberg and “Game of Thrones” actor Liam Cunningham decided to board the latest terrorist-propaganda mission aboard the Madleen with the stated goal of breaking the maritime blockade imposed by Israel on Gaza, they and their fellows were knowingly taking their lives in their hands, and bear the sole responsibility for any outcome.

What Rules Guide Maritime Blockades?

Maritime blockades have been in existence for hundreds of years.¹ In modern warfare, maritime blockades were explicitly mentioned in the 1856 Declaration of Paris Respecting Maritime Law,² with more detailed requirements set out in the 1909 London Declaration on Naval Warfare.³ Most recently, the subject of maritime blockades was also extensively addressed in the 1994 San Remo Manual on International Law Applicable to Armed Conflicts at Sea.⁴

According to these rules, a blockade is legal if it meets certain cumulative requirements:

1. A blockade shall be declared and notified to all belligerents and neutral States.⁵

2. The declaration shall specify the commencement, duration, location, and extent of the blockade and the period within which vessels of neutral States may leave the blockaded coastline.⁶

3. A blockade must be effective⁷ – i.e., maintained by forces that are sufficient to render ingress or egress of the blockaded area dangerous.

4. A blockade must not bar access to the ports and coasts of neutral States.⁸

5. A blockade must be applied impartially to the vessels of all States.⁹

If a blockade conforms with the above requirements, the party that implemented the blockade may, if it has reasonable grounds to believe that a merchant vessel¹⁰ intends to breach the blockade, act to capture the vessel or even, if the vessel refuses to heed the warning and desist from an attempt to breach the blockade, attack the vessel.¹¹

To act against a vessel that has the clear intention of breaching a blockade, the party that implemented the blockade does not have to wait until the blockade is actually breached.¹²

Israel’s Maritime Blockade on Gaza

After Hamas, an internationally designated terrorist organization, took control of the Gaza Strip, and after terrorists from Hamas and other terrorist organizations fired thousands of explosive projectiles indiscriminately targeting Israel’s civilian population, the Government of Israel imposed a naval blockade on the coast of the Gaza Strip on January 3, 2009. The order was designed to prevent weapons, terrorists, and money from entering or exiting the Gaza Strip by sea.

The notification of the blockade was published on the websites of relevant Israeli agencies, issued through a formal Notice to Mariners, and broadcast on maritime radio, with direct conveyance to the relevant flag states. The order stipulated the area subject to the blockade and met the other temporal and geographic requirements set out in the San Remo manual.

The maritime blockade was imposed only after other options were considered and it was determined that a naval blockade provided the most efficient and comprehensive legal tool to confront the prevailing security threat.

The blockade has been in place ever since and has been effectively and consistently enforced by Israel, inter alia, in response to repeated attempts by the terrorists, their supporters, and other protagonists. The most infamous of these attempts was in May 2010, when activists from the IHH organization attempted to breach the blockade on board the Mavi Marmara.

The UN Confirms the Legality of Israel’s Blockade

After Israel prevented the Mavi Marmara from attempting to breach the maritime blockade of Gaza, the United Nations Secretary-General appointed a Panel of Inquiry to examine the events.

In its report,¹³ after examining the circumstances, the Panel of Inquiry concluded “that Israel’s naval blockade was legal.”¹⁴

Summing up the danger of attempting to breach a legal maritime blockade, the UN Panel of Inquiry added:¹⁵

Once a blockade has been lawfully established, it needs to be understood that the blockading power can attack any vessel breaching the blockade if after prior warning the vessel intentionally and clearly refuses to stop or intentionally and clearly resists visit, search or capture. There is no right within those rules to breach a lawful blockade as a right of protest.

The October 7 Massacre and the Maritime Blockade of Gaza

While the blockade has been in force since 2009, its critical importance received renewed justification following the October 7 massacre. Responding to the massacre, Israel’s government set three primary goals for the current war:

1. Destroy Hamas’s military capabilities.

2. Dismantle Hamas’s governance capabilities.

3. Free the hostages.

To destroy Hamas’s military capabilities and dismantle its governance capabilities, Israel needs to ensure, among other things, that it prevents Hamas from rearming and from receiving funds that it critically needs to support both its terrorist activities and its governance mechanisms. Hamas must be isolated from obtaining weapons and suffocated financially.

The maritime blockade of the strip serves explicitly these functions. Its legality, as recognized, among others, by the UN Panel of Inquiry, has only been reinforced, in particular since Israel seized control of the area adjacent to the border with Egypt – known as the Philadelphi Corridor – and has substantially cut off the flow of arms and funds from to Hamas, from Egypt.

The Propaganda War of Images

Israel’s war with the genocidal Gazan terrorists is not only kinetic but rather also a war against terrorist propaganda. In this context, Thunberg, Cunningham, and their friends aboard the Madleen are nothing more than useful idiots promoting the alleged right of the terrorists to “resist” (including by massacring women, children, and the elderly), undermining Israel’s right to self-defense and the right to protect its citizens against genocidal terrorists and echoing the false accusations against Israel.

As noted above, to maintain its legality, the blockade must be effectively enforced; Israel cannot selectively enforce it. Thus, if Israel is to preserve the legality of the blockade, it is certainly justified to prevent Thunberg, Cunningham, and their friends from breaching the area included in the blockade and from attempting to reach Gaza. If Israel does not effectively enforce the blockade, including, by capturing or, if necessary, attacking the vessel, it risks losing one of the most effective measures needed to win the war.

While Hamas, Thunberg, Cunningham, and their friends are engaging in an opaque publicity stunt, they should not forget, as the UN Panel of Inquiry noted, “Breaching a blockade is therefore a serious step involving the risk of death or injury.”

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Notes