Last Thursday, China introduced a new national security law for Hong Kong – its most serious violation of the “one country, two systems” principle since Britain handed over the territory in 1997. In 2003, similar laws were proposed but mass protests prompted Hong Kong’s chief executive to drop the bill. This time, the law was not proposed by Hong Kong’s legislature but by China’s parliament, which passed it by a vote of 2788 to 1.

The Chinese Communist Party wants to end the pro-democracy protests that erupted in Hong Kong last year and to demonstrate its control over the territory. It is willing to weaken Hong Kong’s rule of law, even if this prompts an exodus of foreign firms and undermines Hong Kong’s status as a global commercial hub.

The outlook for Hong Kong – and the rights of its 7.3 million residents – is bleak. China’s hostile takeover is likely to continue. Canberra will need to consider how strongly to respond, and the price it will pay to do so, because Australia has a direct stake in the future of Hong Kong.

The national security law, for instance, may leave Australians and other foreigners in Hong Kong subject to dubious arrests by Chinese authorities. This is a phenomenon that has occurred on the mainland, sometimes as retribution by Beijing for the policies of foreign governments. Hong Kong has one of the largest populations of Australian expatriates, numbering about 100,000 people.

Within Australia, there is also a large community of people with heritage ties to Hong Kong, including 100,000 people who were born there. This community has helped to deepen Australia’s commercial relationship with Hong Kong, which is among Australia’s top fifteen trading partners.

But Australia’s response to future unrest in Hong Kong will incur a heavy price from China. Following Australia’s recent push for an inquiry into the origins of COVID-19, China curbed imports of Australian beef and barley. The economic fallout from a clash over Hong Kong would be worse, because the Communist Party has staked its pride – and the integrity of its current national borders – on the city’s future.

The difficulty for Australia is that any protest against China’s conduct is likely to be ineffective. The Chinese Communist Party will not be swayed. And yet, Australia cannot stand by and condone China’s unlawful and oppressive behaviour. It should be willing to pay a price, and it should be clear about the message it is trying to deliver. When it calls for Beijing and others to respect individual freedoms and the rule of law, that call will be strongest if delivered in concert with other nations.

When the national security law was first proposed, Australian foreign minister Marise Payne issued a joint statement with her counterparts from Britain and Canada, both fellow Commonwealth democracies. Last week, after the law was passed, Australia, Britain and Canada were joined by the United States. This turned the condemnation into a statement from the Anglophone West.

New Zealand, which, along with these four countries, is a member of the Five Eyes intelligence alliance, did not join them in making a collective statement. Instead, it condemned China independently, as did Japan. European leaders also expressed concern.

Australia should try to expand and diversify its coalition of condemnation and develop a unified international approach to Hong Kong. This will amplify the criticism of Beijing and give Australia diplomatic cover. But Canberra needs to start working on assembling such coalitions in advance – the signatories to joint statements should not be determined by who hastily took Canberra’s calls. China’s creeping and premature takeover of Hong Kong is almost certain to continue, and, unfortunately, Canberra’s diplomatic preparations are unlikely to be in vain.