On July 13, the US State Department issued a tough statement on the South China Sea issue, denying China's claims. Then, on July 22, the United States ordered China to cease all operations at its consulate in Houston. China responded in kind and ordered the closure of the US consulate in Chengdu. These episodes illustrate the deteriorating relations between the two countries, which have led many scholars and commentators to worry about a “new cold war” between China and the US. Interestingly, but perhaps not surprisingly, Australia – an important ally of the United States in the Asia-Pacific region – submitted a statement to the United Nations secretary general on July 23, saying that it rejected any claims, including “historic rights” or “maritime rights and interests” in the South China Sea by China that are inconsistent with the 1982 United Nations Convention on the Law of the Sea. In the history of exchanges between China and Australia, this was probably Canberra’s toughest diplomatic statement towards China following the establishment of diplomatic relations in 1972. While almost everyone has been focusing on deteriorating Sino-US relations, Sino-Australia relations have in fact also been experiencing an unprecedented cold snap. In the statement to the UN, Australia said there was no legal basis for China to draw straight baselines around the offshore archipelagos in the South China Sea. As a non-claimant and extraterritorial country, Australia has long been concerned about freedom of navigation and peace and stability in the South China Sea, keeping a low-key profile and neutral attitude. However, in the past few years, Canberra’s attitude towards the South China Sea issue has changed significantly, taking a more high-profile, interventionist posture. At the diplomatic level, Australia has raised concerns about China's activities in the South China Sea in recent years. In terms of maritime activities, Australia frequently conducts joint military exercises with the United States and the Philippines in the South China Sea. This is in addition to sending maritime law enforcement ships into the South China Sea and visiting neighbouring countries. Australia’s statement to the UN marked Canberra's complete abandonment of its neutral position on the disputes over territorial sovereignty and maritime jurisdiction in the South China Sea. Normal international practice would see most non-claimant countries maintain neutrality with regard to unresolved territorial sovereignty disputes. Since third parties with no direct interest in a particular territorial dispute may lack a full understanding of the history and realities of the situation, any inappropriate statements could end up damaging relations between the relevant countries as well as the international order, not to mention that nation’s own international reputation. Must Australia choose between the US and China? Britain recently announced its abandonment of Huawei's 5G equipment, in part at least due to “geopolitical” reasons following pressure from the Trump administration. So it may be reasonable to assume that Australia, as another traditional ally of the United States, would follow Washington’s stance – in this case on the South China Sea issue. In addition to denying China’s claims on maritime rights and interests, Australia also raised objections about Chinese sovereignty over the Paracel and Spratly Islands in its UN statement. China does have disputes with other claimants over territorial sovereignty in the South China Sea. In Beijing’s view, the disputes have been caused by other countries illegally occupying islands and reefs since the 1970s. So, was Australia’s choice of sides in the South China Sea dispute driven by its respect for the values of international law and the ideals of fairness and justice? Perhaps not. Rather, it would seem that its decision had more to do with pragmatic political considerations. The decline in mutual trust between China and Australia has been evident for some time and has gradually affected relations. Australia said in April that it would support an independent investigation into the origins and spread of the Covid-19 pandemic. In response, China imposed import bans and additional tariffs on Australian meat and barley in May and issued warnings to its citizens against travelling to and studying in Australia. After the national security law for Hong Kong was passed, Australia suspended its extradition agreement with the special administrative region. And, in early July, Australian warships operating in the South China Sea confronted Chinese naval warships in waters near the contested Spratly Islands. It is regrettable that Sino-Australian relations have reached this low point, especially as, looking back, there have been many bright moments in the relationship. Australia, for example, was one of the first Western countries to provide aid after China's reform and opening up. Australia is most concerned with freedom of navigation in the South China Sea. Given that such operations have not been affected in the region, Canberra’s policy shift would appear to be based more on its efforts to maintain and consolidate the US-led regional order based on an Asia-Pacific alliance. Ding Duo is an associate research fellow at the National Institute for South China Sea Studies in Hainan, China