Editor's note: Zachary Abuza is a professor at the National War College of the United States, which is is a school in the National Defense University. He wrote this article exclusively for Tuoi Tre News.

2015 was less fraught for Vietnam in the East Vietnam Sea. China did not repeat its aggressive stance by placing the HYSY-981 oil rig clearly on Vietnam's continental shelf, provoking another direct conflict.

But Chinese actions in 2015 laid the ground work for far greater challenges to Vietnam's national interests in the years to come. In particular, the rapid construction of six islands in the Spratly archipelago has created new facts on the ground and the ability to continually enforce its sovereign claims. 

2016 has the potential to be a watershed year in the East Vietnam Sea.

The Permanent Court of Arbitration is expected to rule on the merits of the Philippine suit by mid-2016. Having roundly rejected the Chinese argument that it has no jurisdiction, the PCA is likely to rule against China on most of the merits.

China has steadfastly refused to accept the PCA's jurisdiction and made a nonsensical declaration that in order to "uphold international law" it will ignore and not be bound by the PCA's ruling. China has painted itself into a corner, and if it is not to appear as a complete bully with any regard for international law and norms, it will have to find a way to back down.

Already there are signs that some Chinese diplomats and lawyers are unhappy with the government's losing legal strategy. Yet it is very hard to see China accepting the ruling, even if doing so is in its long-term national interests.

If anything, China may continue its island building. China has a fleet of dredgers that they will not decommission. And as the legal basis for the 9-dash line gets legally annihilated, it will be more important than ever to physically exert control. The government has clearly signaled that no matter how the PCA rules, their sovereignty and physical control will never be surrendered.

China will certainly continue to militarize the islands. While Beijing may opt for a cooling down year and avoid military confrontation in 2016, it is clearly putting in place the capabilities to engage in Anti-Access/Area Denial (A2AD) operations and to enforce an air defense identification zone (ADIZ). It will justify its militarization as self-defense in the face of foreign freedom of navigation operations (FONOPs) that are intended to reject China’s legal claims.

Much of the work in denying access to the region will fall to China's rapidly growing maritime militia, backed by coast guard and naval vessels in an integrated program. This strategy has effectively denied Vietnamese fishermen from exploiting the natural resources in the East Vietnam Sea, while garnering a muted diplomatic response.

With a slowing economy, horrific levels of pollution, and endemic corruption, President Xi Jinping needs an assertive and highly nationalist foreign policy to shore up declining legitimacy.  There will be considerable political and diplomatic costs to rejecting the PCA ruling, but these have already been factored in and they are deemed acceptable to the leadership. Indeed, the cost of acquiescing to the PCA ruling is probably politically more fraught for the Chinese leadership.

And while the Philippine lawsuit could be an enormous victory for the rule of law, it is unlikely that other claimants will quickly follow suit, for fear of Chinese bullying and punitive military and economic responses.

But so much depends on politics throughout the region. And 2016 will see new governments in power in many of the key states, not just Vietnam.

The Philippines is in the midst of a closely fought presidential election. President Benigno Aquino has done much to refocus his country's weak military from internal security to territorial defense. And while his military modernization program has been very modest by regional standards, it has been an important step in conjunction with renewed ties with the United States and their courageous legal strategy. But the leading candidate to succeed Aquino has already hinted that he will pursue a less confrontational tack. This has already prompted concerns that he could actually withdraw the arbitration altogether, if the PCA does not rule by late-May. Moreover, the Philippine Supreme Court has twice delayed its ruling on the Enhanced Defense Cooperation Agreement with the United States, which would deepen the alliance. To date it has been unclear whether it is the result of judicial indecision or whether the court simply does not want to get out ahead of the political process and make such a sensitive ruling in an election year.

Malaysia became quietly more assertive in 2015. But Prime Minister Najib Razak is mired in an enormous corruption scandal that has the potential to bring down his government.

While Indonesian President Joko Widodo continues to describe the "Maritime Fulcrum" as the centerpiece of his foreign policy, the country's over-reliance on raw material exports to China weakens his position. Moreover, Indonesia's inability to come up with a national strategy on the East Vietnam Sea issue will continue to result in bureaucratic competition and mixed messages.

Although Japanese Prime Minister Shinzo Abe has pushed through a new interpretation of the Constitution, overseen a rise in military spending, increased defense relations with Southeast Asian states, and reinvigorated the alliance with the U.S., this has resulted in intensified Chinese challenges to Japan's sovereign claims. This could result in a significant withdrawal of public support for Abe amongst the Japanese public whose pacifism runs deep. So while Abe may flirt with the idea of joining FONOPs in the East Vietnam Sea, China will respond with increased patrols and challenges in the Senkaku islands, taxing Japan's defense and maritime law enforcement capabilities.

But no country's policies could be upended by politics more than the United States. In late 2015, and after much internal debate, the U.S. finally engaged in FONOPs, with a commitment to continue them on a regular and routine basis. But then and since, the U.S. government has repeatedly botched the strategic communication sending mixed signals and undermining the confidence of allies and partners. This indicates that there are still key actors in the government who do not fully endorse them, fearful that it will further complicate an already complex bilateral relationship with China.

In the final year of office, President Barack Obama will be focused on defeating the Islamic State and pushing through the last of his domestic agenda (including the passage of the TPP) through a Republican Congress that is determined to thwart him ahead of national elections in early-November. A more confrontational approach towards China will be driven more by electoral politics than anything else.

There is a lot of uncertainty in the political landscape in 2016 that the newly elected Vietnamese leadership will have to navigate. While I expect little in the way of major policy changes from Vietnam following the 12th Congress, the changing international context will influence their policymaking. But calm waters don't make a skilled mariner.