Legal protection of maritime blockade operations in high-end naval warfare

Maritime blockade operations are a common method used in foreign maritime armed conflicts and are also the main form of naval military exercises for our military. They can coordinate with landing operations to encircle the enemy and cut off their supply lines. According to international conventions, as long as the restrictions on means and methods of warfare in international law are followed, and humanitarian principles are adhered to, the rules of maritime blockade operations are equally applicable to domestic armed conflicts. This article primarily discusses the legality of implementing maritime blockades and the general blockade rules that should be followed, clarifying the delineation of blockade areas, the application of blockade means and methods, and the adherence to humanitarian rules.

Maritime blockade operations are conducted by naval forces alone or in coordination with other military branches to control specific maritime areas or sea lanes, isolating the enemy's coasts and islands from external contact. The purpose of maritime blockade operations is to exert economic pressure on the enemy, preventing the entry and exit of ships, aircraft, and submarines from all countries (including enemy and neutral nations) into specific ports, airports, or coastal areas controlled by the enemy or occupied by them, thereby cutting off all maritime trade of the targeted nation.

Its main features include: First, maritime blockade operations focus on the economy of the blockaded area and constitute a strategic action. Second, the ships conducting the blockade are stationed beyond the range of coastal defense weapons, resulting in a larger blockade area. During the blockade, the blockade forces inevitably prevent maritime trade at the target country's ports, causing significant impact on the target country's economic trade. Unlike full-scale offensive operations that require the mobilization of substantial military forces, blockade operations can be conducted by ships or aircraft, combined with missile strikes to besiege military targets.

Currently, maritime blockade operations are the primary form of our naval military exercises. Therefore, studying and discussing the legal issues related to maritime blockade operations holds significant practical importance.

I. Analysis of the Legitimacy of Maritime Blockade Operations in Domestic Armed Conflicts

Blockade in international law is a means of warfare involving actions between two sovereign states, which requires both the blockading and the blockaded parties to be independent sovereign states. Strictly speaking, domestic armed conflicts are internal affairs of a state and are not within the scope of international law. Therefore, the blockade implemented in domestic armed conflicts differs from the general meaning of blockade in maritime warfare law. It is the exercise of national jurisdiction by the sovereign state itself. The issue here is whether the maritime blockade in civil wars is legally valid.

Article 3 of the Additional Protocol on the Protection of Victims of Non-International Armed Conflicts in the year explicitly states that a government has the "responsibility to maintain or restore domestic law and order or to defend national unity and territorial integrity by all lawful means." Article 7 of Section 2 of the United Nations Charter stipulates: "Nothing in the present Charter shall authorize the United Nations to intervene in matters which are essentially within the domestic jurisdiction of any state and shall not require the Members to submit such matters to settlement under the present Charter." These provisions clearly define that the timing and means by which a sovereign state takes action to prevent national division and maintain national unity and integrity are entirely matters of domestic jurisdiction.

Therefore, in the context of domestic armed conflicts, maritime blockade operations should be understood as the sovereign right of a state to independently take all appropriate actions and methods to handle all affairs within its territory, including the use of maritime blockade measures to close certain ports, airports, and maritime areas within the country. The implementation of maritime blockade during domestic armed conflicts is fully justified under international law and is a legitimate right to achieve national unity. Not only is it impermissible for other countries to interfere, but they are also prohibited from requesting the United Nations General Assembly to discuss the legality of such actions.

II. The implementation of maritime blockade operations should comply with the general requirements of international law.

(I) The designation of maritime blockade zones

Maritime blockade involves a large area of sea, often affecting the maritime shipping and trade of third countries, and should strictly delineate the blockade area in accordance with international law. The 1909 London Declaration stipulates that the belligerent parties can only limit the blockade area to the coasts and ports of the opposing side, and may not set up blockades in the high seas and international straits, nor in the territorial seas of neutral countries. According to Articles 55, 56, and 58 of the United Nations Convention on the Law of the Sea, blockades can be implemented within a country's territorial sea and internal waters, but there is no explicit provision for setting up blockades in the exclusive economic zone and the high seas. However, based on the principle of freedom of the high seas, it should be presumed to be legal to set up blockade areas in the high seas.

(2) Requirements for Maritime Blockade Measures and Methods

The maritime blockade system is a product of international customary law and an effective military means of maritime warfare. By imposing a blockade, maritime powers can prevent the targeted coastal state from engaging in any maritime trade with any other country, block all maritime traffic of the blockaded state, and extend the blockade to neighboring ports of the blockaded state that can be used for transportation, thereby causing severe economic damage to the blockaded state. Therefore, the core element of a blockade is to cut off the maritime trade between the blockaded state and other countries. Only by actually deploying military forces to implement the blockade can this strategic objective be achieved. Consequently, the blockade must be effective.

(III) Identification and Handling of Violations of Maritime Blockades

The determination of breaking the blockade should meet two conditions: one is the objective condition, which is the fact of breaking through the blockade line; the other is the subjective condition, which is knowingly violating the blockade, having received the public declaration and notification of the blockade, and still passing through the blockade line. It should be noted that the following situations do not constitute a breach of the blockade line: one is entering the blockade area due to the need for repairs, severe weather, lack of fresh water or food; two is a ship already within the blockade area before the blockade and sailing out empty; three is a ship employed by a neutral country to transport its distressed crew members back from the blockade area.

III. Humanitarian Protection Requirements to be Followed in Maritime Blockade Operations

Currently, few economies in the world can achieve complete self-sufficiency in resources, energy, and food. Maritime blockade operations are the most direct and effective means of destroying a modern economic system. As the blockade prolongs, the containment of trade in the blockaded region will inevitably cause severe damage to the lives of civilians. During the months of January to March, the UK seized a total of over 100,000 tons of goods bound for Germany. The majority of these were minerals, metals, and related products, followed by oilseeds and food products.

IV. General Implications of Maritime Blockade Operations Rules in Domestic Armed Conflicts for China

Currently, the military technology and weaponry used in maritime blockades during high-end naval battles are constantly evolving, and the tactics for breaking through these blockades are also increasing. At the same time, with the growing sophistication of maritime law, the rules and restrictions on blockade actions in naval warfare are becoming more numerous, making maritime operations increasingly open and transparent. In the context where the laws of armed conflict are widely recognized by the international community, we must use legal means to strengthen the protection of maritime blockade actions, ensuring that these actions not only achieve victory but also gain political initiative.