Mandate of Heaven: An ADIZ in the South China Sea
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Mandate of Heaven: An ADIZ in the South China Sea


Cabo Verde, an island nation off the coast of West Africa, holds a unique distinction. According to a report issued by the U.S. Congressional Research Service, Cabo Verde is one of just 27 nations (including China) of the 167 states party to the United Nations Law of the Sea Convention (UNCLOS) that claim the ability to regulate or prohibit foreign military activity beyond the territorial sea and within an exclusive economic zone (EEZ). The United States has long maintained otherwise: UNCLOS, which established EEZs and reflects existing customary international law, only codified sovereign rights that are related to regulating economic activities within EEZs and are subject to the high seas freedoms, particularly navigation and overflight. As I ambled across the cobble stone streets of Praia, it seemed peculiar that the legal claim of a tiny island nation in the Atlantic Ocean could make waves in the South China Sea (SCS), but such is the dynamic and complexity of this geopolitical flashpoint.

One test of a rising power is its ability to effectively bend international law to legitimize tactical maneuvers and strategic objectives. Customary international law accommodates such an approach given its evolutionary nature and “bandwagoning” propensity (as revealed through state practice and opinion juris). In response, status quo powers are more likely to rely on treaty regimes, which are characterized by rigidity, institutionalization, and contractual consent. In the case of the SCS disputes, China is wielding custom like a sword and shield, while the United States and its Pacific allies seek refuge in the fixed terms and procedures of treaties like UNCLOS.

This heated legal drama has entered the staid halls of the Permanent Court of Arbitration at The Hague. On January 22, 2013, the Philippine’s initiated compulsory arbitration proceedings under UNCLOS “with respect to the dispute with China over the maritime jurisdiction of the Philippines” in the SCS. Since the arbitration’s commencement, China has refused to accept or participate in the arbitration on the basis that the Arbitral Tribunal lacks jurisdiction. On December 7, 2014 (notably prior to the filing deadline the Arbitral Tribunal set for a Counter-Memorial), Beijing published a “Position Paper” reiterating its refusal to participate and arguing that the subject-matter of the arbitration concerns competing sovereignty claims that lay beyond the interpretation or application of UNCLOS.

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China’s posture has not stopped the Arbitral Tribunal from continuing the proceedings. The Arbitral Tribunal has interpreted Article 9 of Annex VII to UNCLOS and Article 20 of the Rules of Procedures (as adopted by the Arbitral Tribunal following a period of notice and comment) as enabling the tribunal to rule on objections to its jurisdiction and the admissibility of the Philippine’s claims, as set forth China’s Position Paper. To assist in evaluating the issues of jurisdiction and admissibility, the Arbitral Tribunal commenced a multi-day hearing on July 7, 2015 due to conclude this week.

In the meantime (and seemingly as a rejoinder to the arbitral calendar), China has been changing facts on the ground in the SCS. In particular, China has engaged in a series of controversial land-reclamation activities in the Spratly Islands (Nansha islands) and Scarborough Shoal (Huangyan island). Chinese reclamation has created over 2,000 acres (809 hectares) of artificial landmasses on Chinese-occupied reefs that are subject to multi-national disputes and located in major global thoroughfares, maritime and airspace. This activity continues despite the express terms of Article 60 of UNCLOS, which state that artificial islands, installations, and structures are not islands and do not generate any territorial sea or other maritime zones. China’s Position Paper offers a succinct (if conclusory) rebuttal based on custom: “Chinese activities in the South China Sea date back over 2,000 years ago.”

Air Defense Identification Zone

Beijing also recently threatened to create new realities in the air through the establishment of an aircraft defense identification zone (ADIZ). Depending on its contours, the zone could overlap with existing controlled areas of international airspace (for example, parts of the Manila FIR and Ho Chi Minh FIR), extend over disputed territories and maritime zones, and cover Chinese occupied formations in the SCS. U.S. officials believe that one objective of China’s reclamation activities, including construction of an aircraft landing strip, is an increased ability for more sustained air operations in the SCS (necessary for enforcing an ADIZ far from the Chinese coastline).

Considering that the first powered flight occurred on December 17, 1903, and international air navigation rights were first memorialized following World War I, establishing an ADIZ would have to be considered a more recent activity for China in the SCS (and not a relic of the Zhou dynasty). Indeed, the state practice of ADIZs only dates back to 1950 when the United States first established the buffer zones to defend against the threat of long-range Soviet bombers.

Contrary to some claims, ADIZs are not an extension of sovereign airspace under current customary international law. For instance, recognizing the limits of ADIZs, in 1988 the United States altered its ADIZs in the Gulf of Mexico and off the coast of southern California to account for the sovereign airspace of Mexico. ADIZs are certainly not a means to claim new or disputed territory. Moreover, the legal basis for ADIZs does not arise from UNCLOS maritime zones.

Instead, an ADIZ is an area of airspace, adjacent to, but beyond the national airspace and territory of the state, where aircraft are identified, monitored, and controlled in the interest of national security. ADIZs are legally grounded in the inherent right to self-defense under customary international law and Article 51 of the United Nations Charter. Therefore, the geographic scope and enforcement of ADIZ must adhere to the principles of necessity and proportionality, as evolved since Daniel Webster’s articulation during the Caroline affair in 1851. An indeterminate security zone in international airspace or linked to an EEZ would not be necessary or proportionate, or consistent with other principles of international law such as the freedom of overflight. That is why U.S. law and policy limit administration of ADIZs to aircraft that intend to enter or depart from U.S. national airspace and territory.

Regardless of prior precedent, China may propose to amend customary international law in relation to ADIZ by creating a new “Mandate of Heaven” in the SCS. The declaration of an ADIZ could lead to the material enforcement of China’s assertion of “undisputed sovereignty” and “related rights and jurisdiction” in nearly all of the SCS. For example, the most extreme scenario would be if the ADIZ encompassed the entirety of Beijing’s “dashed-line” claim encircling the island waters of the SCS, an area equal to about 22 percent of China’s existing land territory and the vast majority of airspace in the SCS. Beijing may feel compelled to align the ADIZ with the dashed-line map in order to preserve, or at least not undermine, its claim.

Note that the breadth and logic of this potential action would extend beyond past Chinese attempts to invoke security rights in the airspace above the EEZ in the SCS (e.g., the EP-3 incident of April 1, 2001) or the establishment of an ADIZ above the East China Sea (where China at least mimicked identification and control rules associated with extraterritorial ADIZs). A state’s legal ability to administer and use force to secure its sovereign territory and accompanying airspace is much broader than the right to self-defense in international airspace or within an ADIZ.

If China proclaimed an ADIZ encompassing the dashed-line map and remained consistent with its claims of “undisputed sovereignty” in the SCS, then the airspace in the zone would have to be administered and defended like national airspace. Accordingly, any remaining strategic ambiguity provided by the nine-dashed claim would dissipate, and so would the freedom of action among opposing parties. In other words, a Chinese ADIZ would significantly “complicate and escalate disputes” in the SCS and threaten “peace and stability,” to borrow from the 2002 Declaration on the Conduct (DOC) of Parties in the South China Sea.

The United States and affected ASEAN members would more than likely challenge Beijing’s proposal by practicing the freedoms of navigation and overflight. Would Beijing intercept and shoot down non-compliant Filipino civil flights or U.S. Navy aircraft crossing a Chinese ADIZ in the SCS? Would traversing foreign air carriers be forced to pay overflight fees for passing above Chinese “territory”? If China did not take enforcement action against foreign civil and military aircraft, would this be an acknowledgment that the ADIZ was not Chinese sovereign airspace?

To be sure, any use of an ADIZ to assert a sovereignty claim in the SCS would be a significant departure from existing customary international law. It would also be a dangerous gamble for a rising power. The bandwagoning effect may be that of a rush to Washington’s embrace. Customary international law like the traditional Mandate of Heaven is not a naked assertion of power, but rather an ongoing proffer based on the responsible exercise of authority – and subject to rejection.

Roncevert Almond is an international lawyer and partner at The Wicks Group. He has advised the U.S.-China Economic and Security Review Commission on legal issues concerning ADIZ and is author of a forthcoming article on ADIZ in the Harvard National Security Journal. The views expressed here are strictly his own.

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