Vietnam has signaled it may take China to international arbitration over their South China Sea disputes, a move that would inevitably exacerbate Hanoi’s maritime tensions with Beijing and shift its stance more closely in line with the United States.

Deputy Foreign Minister Le Hoai Trung, speaking at a conference in Hanoi, said last week that Vietnam was considering alternative measures apart from bilateral dialogue, including “mediation, negotiation, arbitration and litigation measures.”

“The UN Charter and UNCLOS [the United Nations Convention on the Law of the Sea] 1982 have sufficient mechanisms for us to apply those measures,” Vietnam’s top diplomat said, referring to the legal code that governs international maritime regulations and norms.

The legal threat comes as the two rival claimants have been locked in a months-long standoff over the contested Vanguard Bank, an energy-rich feature which lies within Hanoi’s exclusive economic zone (EEZ) that China claims as its own.

The high seas showdown, where both sides have deployed naval vessels, has threatened to tilt towards armed confrontation on several occasions, according to news reports.

If Vietnam does seek to internationalize the sea disputes through court action, recent history shows Beijing will not take kindly to the legal threat.

The resort to legal action would also more clearly align Vietnam with its budding ally the US, which has consistently advocated that customary international law should be upheld in the strategic waterway.

US President Donald Trump and Vietnamese Prime Minister Nguyen Xuan Phuc (L) at the Government Office in Hanoi on February 27, 2019. Photo: Saul Loeb/AFP

The Philippines won an arbitral case against China at the Permanent Arbitral Court at The Hague in July 2016, a judgement that ruled based on UNCLOS provisions against the legality of China’s nine-dash line map which claims nearly 90% of the South China Sea.

Although a signatory to the UNCLOS, China rejected The Hague’s ruling as “a piece of trash paper”, and subsequently warned the Philippines against pressing the arbitration award in global fora.

Under Beijing-leaning President Rodrigo Duterte, the Philippines has mainly dialed down its sea tensions with China while playing down the significance of its legal victory, which notably lacked an enforcement mechanism.

The Filipino president controversially announced just months after taking office that he would “set aside” the arbitration award in the interest of developing warmer ties with China, which has offered large-scale investments in the country.

Legal experts believe Vietnam would likely be successful in pushing for a compulsory arbitration case against China at The Hague, similar to the Philippines’ case.

Any ruling, they say, would likely reaffirm the incompatibility of China’s nine-dash line map with modern international law and give Hanoi firmer footing to assert its sovereign rights over energy and fishery resources within its EEZ and continental shelf now challenged by Beijing.

At the same time, it is unlikely that any Hague ruling would affirm Vietnam’s own island claims in the area, including over the Spratly and Paracel chains, since sovereignty disputes require mutual consent for international arbitration.

Vietnam is now the lone regional voice advocating for tougher countermeasures against Beijing’s rising assertiveness in the sea.

Hanoi has repeatedly warned about China’s militarization of its artificially reclaimed islands and ever-larger deployment of maritime militia and coast guard forces in sea areas, calls its co-members in the Association of Southeast Asian Nations’ (ASEAN) have largely played down.

Ahead of its assumption of ASEAN’s rotational chairman in 2020, taking over from Thailand, Vietnam is already signaling it will bid to forge a tougher bloc stance on China’s actions in the South China Sea.

Hanoi has also championed the cause of a legally binding Code of Conduct for the South China Sea, a long-negotiated regime to ensure peaceful management of disputes among claimant countries. Vietnam, the Philippines, Malaysia, Brunei and Taiwan all have rival claims with China in the sea.

China has promised to finalize the proposed CoC within the next two years, yet there are few indications that Beijing would be willing to relinquish control of areas and features it has recently consolidated through military means.

Speculation on Vietnam’s intent to take China to court first arose last month when an influential local think tank held a public forum at which experts recommended international arbitration to “identify who is right and who is wrong in this matter.”

“Most of the attendees agreed that Vietnam needs to change its foreign policy, including coming up with a proposal for further developing relations with the US, to rid itself of Chinese influence,” one of the Vietnamese participants told Radio Free Asia, a US Congress-funded news service.

Chinese PLA Navy soldiers on a naval vessel in the South China Sea. Photo: Twitter

Days before, in a speech at the UN General Assembly, Vietnamese Foreign Minister Pham Binh Minh called on Beijing to “exercise restraint and refrain from conducting unilateral acts, which might complicate or escalate tensions at sea, and settle disputes by peaceful means.

“Vietnam has on many occasions voiced its concerns over the recent complicated developments in the South China Sea, including serious incidents that infringed upon Vietnam’s sovereignty,” the Vietnamese chief diplomat said.

At the same time, Vietnam has ramped up its strategic partnership with the US, a former battlefield adversary but now key ally in the South China Sea disputes.

In its Indo-Pacific Strategy paper released earlier this year, the Pentagon openly celebrated how its strategic partnership with Hanoi has “grown dramatically over the past several years, as symbolized by the historic March 2018 visit of a US aircraft carrier for the first time since the Vietnam War.”

The US has also expanded its maritime defense assistance to Vietnam, which has recently received T-6 trainer aircraft, Scan Eagle Unmanned Aerial Vehicles, a retrofitted US Coast Guard high-endurance cutter and several patrol vessels.

The two sides have also expanded “annual training exchanges and activities to enhance bilateral cooperation and interoperability with the Vietnam People’s Army, Air Force, Navy, and Coast Guard,” according to the same Pentagon report.

Vietnamese military officials watch as the US Navy (USN) Arleigh Burke Class Guided Missile Destroyer USS Curtis Wilbur (DDG 54) prepares to moor at the Vietnamese port of Da Nang. Photo: Facebook/US National Archives

David Stilwell, US assistant secretary of state for East Asia and the Pacific, openly called on regional states ahead of the recently concluded ASEAN Summit held in Bangkok to follow in Vietnam’s footsteps.

“This is your turf, this is your place. Vietnam has done a good job of pushing back. I would think that regarding ASEAN centrality…[it] would join Vietnam to resist actions that are destabilizing and effecting security,” Stilwell said in reference to the South China Sea disputes.

“I ask my ASEAN counterparts what their alternate plan was in this world where we like not to have to choose,” the envoy said, while vowing US support for a regional pushback against Chinese threats to “orderly movement in the use of the oceans.”

“Without security, you can’t have trade,” Stilwell said. Referring to the UNCLOS, which has yet to be ratified by the US Senate, Stilwell maintained that “we do comply and we enforce it” as a matter of customary international law.

“Nobody is better suited to [lead regional efforts] than the US, mostly because we include others in that security apparatus in terms of allies and partners,” he said, with clear reference to Vietnam.

“The fact that they are like-minded is reinforcing and tells us that we are doing something right.”