Neutral Merchant Ships under International Law: Legal Protection, Exceptions and India’s Options

Context

Recent attacks on merchant tankers that claimed the lives of three Indian seafarers have renewed attention on the legal protection of neutral merchant ships during armed conflicts and the circumstances under which they may lawfully become military targets.

Legal Basis

The legal status of neutral merchant ships is governed by three complementary branches of international law:

1. International Humanitarian Law (IHL): Regulates the conduct of hostilities and protects civilians and civilian objects.
2. Law of Naval Warfare: Governs military operations at sea, including attacks, visit and search, capture, naval blockades, and the rights and obligations of belligerent and neutral states.
3. Law of the Sea: Reflected primarily in the United Nations Convention on the Law of the Sea (UNCLOS), it governs maritime zones and navigational rights, many of which are recognised as customary international law.

Protection of Neutral Merchant Ships

1. Neutral merchant vessels are generally regarded as civilian objects and enjoy protection from attack under International Humanitarian Law.
2. This protection extends to commercial vessels carrying civilian cargo, including oil, food, fertilisers and other goods.
3. Under the principle of maritime neutrality, neutral states may continue lawful commercial activities but must not directly support a belligerent’s military operations.
4. Neutral vessels also retain the right of transit passage through international straits, including the Strait of Hormuz.

Circumstances for Loss of Protection

Under the San Remo Manual on International Law Applicable to Armed Conflicts at Sea (1994), a neutral merchant vessel may lose its protection if it:

1. Carries contraband intended for a belligerent.
2. Knowingly breaches a lawful naval blockade.
3. Refuses to stop after a lawful warning.
4. Resists lawful visit, search or capture.
5. Makes an effective contribution to military operations, thereby becoming a legitimate military objective.

Commercial activity alone does not make a neutral merchant vessel a lawful military target.

Legal Status of Oil Tankers

1. Transporting oil does not automatically make an oil tanker a military objective.
2. Oil may qualify as contraband if it is intended to directly support an enemy’s military operations.
3. A commercial vessel may be lawfully targeted only if it makes a direct and effective contribution to military action.
4. The broader “war-sustaining” doctrine, which treats revenue-generating assets as military objectives, remains legally contested and lacks universal acceptance.

Naval Blockades

A naval blockade is lawful only if it is:

1. Officially declared.
2. Effectively enforced.
3. Applied impartially.
4. Conducted in accordance with international law.

Neutral vessels that knowingly breach a lawful blockade may be intercepted, captured or subjected to other lawful enforcement measures.

The legality of a blockade must also satisfy the UN Charter:

1. Jus ad bellum governs the legality of the use of force.
2. Jus in bello governs the conduct of hostilities during armed conflict.

Accordingly, a blockade may comply with the law of naval warfare but still be unlawful if it lacks UN Security Council authorisation or a valid claim of self-defence under Article 51 of the UN Charter.

India’s Legal Options

Under the doctrine of diplomatic protection, India may pursue legal and diplomatic remedies on behalf of its affected nationals by:

1. Seeking official clarification.
2. Demanding accountability.
3. Calling for an independent investigation.
4. Seeking compensation.
5. Raising the matter before appropriate international forums.

Principles Governing the Use of Force

Any attack on a neutral merchant vessel must comply with the following principles of International Humanitarian Law:

1. Distinction: The vessel must constitute a legitimate military objective.
2. Proportionality: Expected civilian harm must not be excessive in relation to the anticipated military advantage.
3. Military Necessity: Force should be limited to what is necessary to achieve a legitimate military objective.
4. Precaution: All feasible measures must be taken to minimise harm to civilians.

Significance

1. Protects civilian shipping and global maritime trade during armed conflicts.
2. Upholds the principles of freedom of navigation and maritime neutrality.
3. Clarifies the legal limits on targeting neutral commercial vessels.
4. Reinforces accountability for violations of international humanitarian and maritime law.

Conclusion

International law seeks to balance military necessity with the protection of neutral shipping and civilian lives. Neutral merchant vessels enjoy broad legal protection and may be targeted only in exceptional circumstances recognised under international law. Adherence to International Humanitarian Law, the law of naval warfare, and the UN Charter is essential for safeguarding freedom of navigation, protecting civilian lives, and maintaining a rules-based international maritime order.