The recent ruling by the Permanent Court of Arbitration regarding the South China Sea dispute only wedges Australia further between the United States and China.

The realist school of international relations argues that a country’s foreign policies are primarily driven by its national interests. While this appears to be a straightforward formula, Australia is increasingly being wedged between two conflicting national interests in the South China Sea.

On the one hand, Australia has strong geopolitical interests in maintaining its alliance with the United States. On the other hand, Australia has strong economic interests in maintaining a positive relationship with China. As China and the United States clash over the South China Sea, Australia is increasingly being forced to make an uncomfortable choice between its interests.

Australia’s geopolitical alliance with the United States was cemented in the early days of the Cold War with the formation of the ANZUS Treaty. Within Asia, Australian troops have fought alongside US troops in both Korea and Vietnam, and Australia has not strongly opposed the US on any international issue since the Suez Crisis in 1956.

Conversely, the United States views Australia as one of its strongest allies in the region. Australia provides the United States with a stable ally in an often unpredictable region, and the US is coming under increased pressure to withdraw troops from other parts of Southeast Asia. President Obama’s ‘pivot to Asia’ thus sees the stationing of 2,500 US marines in Darwin. For Australia, this also provides millions of dollars towards its Northern economy.

However, Australia’s economic interests are also heavily embedded with China. China is Australia’s largest two-way trading partner in goods and services, valued at A$ 155.5 billion in 2015, (up 2 per cent from the previous year). Aside from Australia’s direct trade with China, 91 per cent of Australia’s fuel imports, 60 per cent of Australia’s exports, and 40 per cent of imports travel through the South China Sea, all of which must pass through Chinese military checkpoints.

Yet, while Australia’s national interests lie with both the United States and China, these two countries have conflicting interests in the South China Sea. China makes historical claims over the South China Sea and harbours a strong nationalist sentiment that seeks to reassert naval dominance following a century of humiliation. Additionally, China is interested in the South China Sea’s rich economic resources, particularly oil and gas.

However, the United States also has political and economic interests in the South China Sea. Politically, the United States is wary of China’s increasing military and economic capabilities which threaten to eventually displace the United States. Economically, US $1.2 trillion of US trade passes through the South China Sea.

President Obama has previously pledged to “continue to fly, sail and operate wherever international law allows,” and has sent missile destroyers on freedom of navigation patrols within 12 nautical miles of China’s claims — the conventional limit for territorial waters under international law. Ironically, however, the United States Congress has itself refused to ratify the United Nations Convention on the Law of the Sea, and this has allowed China to deflect US criticism on grounds of hypocrisy.

On its part, Australia has long stated that it has no position on territorial claims in the South China Sea. Australia has conducted air surveillance operations and naval patrols in the region since 1980, despite verbal challenges from China. But, unlike the US navy, Australia has not conducted naval operations within 12 nautical miles of China’s claims. The US has publicly hinted its desire for Australia’s participation in joint operations, but despite reports of bilateral discussions, Australian government officials deny that an express request has been made to this effect.

Australia has, however, taken the position that territorial disputes are best resolved through processes of international law. Following the recent ruling by the Permanent Court of Arbitration, Australia issued a joint statement with the US and Japan, expressing its “strong support for the rule of law” and calling on the parties to abide by the decision.

In response, the Chinese Foreign Ministry gave an unusually blunt warning to Australia that it should “carefully talk and cautiously behave”. It also stated its “hope” that Australia “firmly abide by the promise not to hold a position” on territorial disputes.

It is increasingly clear that China’s behaviour in the South China Sea is not going to change in light of the Court’s decision. Additionally, in recent weeks, President Duterte of the Philippines has signalled an apparent change in the longstanding US-Philippines alliance, and a desire to increase trade and commerce with Russia and China. The extent of this shift remains unclear, but it is possible that the Philippines may accept China’s de-facto control despite the Court’s ruling. Effectively then, the Court’s decision has only further wedged Australia between the United States and China.

Given China’s unusually blunt warnings to Australia, participation in joint freedom-of-navigation exercises with the United States may present a serious risk to Australia’s economic interests. Australia already carries out surveillance patrols, and changing tactics could be seen as an overt threat by China. No other likeminded country has committed to joining the United States, and this would place Australia “conspicuously on its own”. Additionally, such exercises carry the risk of escalation in an already fragile area, and it is unclear how such exercises would change China’s behaviour.

However, in a “remarkably strong response”, polling suggests that 74 per cent of the Australian public are in favour of Australia conducting naval exercises “in an effort to ensure freedom of navigation in the South China Sea”. Given Australia’s strong alliance with the United States, Australia may come under increased pressure “to make its presence felt in the South China Sea beyond statements of diplomatic support for freedom of navigation”.

Whichever path is ultimately taken, Australia may face an uncomfortable choice.

Shmuel Levin has worked on improving security frameworks across the Asia-Pacific as a Policy Officer for UN SCAR and the Pacific Small Arms Action Group. He has previously written for The Diplomat, and has worked on State and Federal policy matters. Shmuel is currently studying Law and International Relations at Monash University.