In East Asia, a rising China has outstanding advantages in its market scale, the capacity of its foreign exchange reserves and commodity prices. Meanwhile, US comparative advantages lie in its alliance system and military bases across the world. It is widely recognized that the ASEAN countries rely on China for economy and the US for security, which is believed by many as the best way for China and the US to reach a balance in East Asia.

However, it is not a healthy coexistence. The China-ASEAN economic relationship will not harm US interests, yet US-ASEAN security ties are built on the basis of countering China.

This is partly due to the territorial disputes between Beijing and some ASEAN nations.  Washington's intervention in the region also matters, which is exemplified by the South China Sea arbitration unilaterally launched by the Philippines.

The dual system where the US is accountable for security and China for economy can hardly work. China attempts to deepen security cooperation with the ASEAN countries via economic ties, but it does not want the cooperation to be upset by territorial disputes, nor does it want these disputes to be made use of by the US. From the US perspective, this is a reflection of China's "Monroe Doctrine," which attempts to drive the US out of Asia.

Washington, on the other hand, tries to reclaim its economic influence in the region by taking advantage of its alliance system. The Trans-Pacific Partnership is a typical example, which is viewed by Beijing as containment against China.

The award of the South China Sea arbitration may bring the China-US contest to new climax. For the US, this is a great opportunity to humiliate and contain China, and to strengthen its military presence in Southeast Asia.

China has already clarified its stance of neither accepting nor participating in the arbitration. The US strives to tar China as a destroyer of international laws, so as to strengthen its status as a leader and a defender of order in the region.

However, the ASEAN countries, squeezed between China and the US, will not passively accept the results of the game. On the contrary, their choice has become key amid the changing roles of China and the US in Southeast Asian geopolitics. Take the Philippines. China has already become the first largest trading partner of the Philippines. However, given territorial disputes, Manila, during Benigno Aquino's term, not only strengthened its security alliance with Washington, but also actively sought alternatives to China economically, for instance, Japan.

Philippine new President Rodrigo Duterte takes a totally different stance. For him, the economy should be prioritized, and territorial disputes with China can be addressed by negotiations. While Aquino took side with the US for security reasons, Duterte develops a friendly relationship with China for economic development.

Duterte's attitude will go against Washington's after the arbitration award is announced. The latter will not take a hands-off attitude to Manila's shifted stance. If Washington gets the upper hand, Manila may be forced to continue to rely on the US for security, and meanwhile be restricted in its economic ties with Beijing. If the situation develops the other way round, the Philippines may grow closer to China economically, and security relations between the two may ease.

Given the US clout in the Philippines and Duterte's strong character, it is still hard to conjecture which side will get an upper hand. The development of the China-US contest in Southeast Asia's economy and security needs to be observed as well. It is certain that in the long run, the contest between a rising China and a powerful US will continue in the region.

More importantly, the US should respect the Philippine citizens and their new government's choice. The territorial disputes between Beijing and Manila have nothing to do with a third party, and it is abnormal for the US to advocate war if the two parties reconcile.

Washington's intention to play an active role in Southeast Asia's security and economy is understandable, but it cannot make decisions for Manila.

The author is an associate research fellow at the Institute of International Relations, Shanghai Academy of Social Sciences. opinion@globaltimes.com.cn