One of the arguments for a peaceful resolution of international disputes is that armed conflict provides a febrile climate for arms races between nations that are not directly involved in the fighting, which can fuel conflict in other parts of the world. A case in point is the Ukraine crisis. It has proved a convenient backdrop for the newly forged Aukus defence alliance of Australia, the United Kingdom and the United States to openly cooperate on weapons development, including hypersonic missiles, countermeasures and electronic warfare capabilities. This was announced in a joint statement by President Joe Biden and prime ministers Boris Johnson and Scott Morrison. They dressed it up “in light of Russia’s … invasion of Ukraine … [and] our unwavering commitment to [respect for] human rights, the rule of law, and the peaceful resolution of disputes free from coercion”. China and Russia are clearly in their sights, China having tested a hypersonic weapon recently and Russia having claimed to be using them in the war in Ukraine. All three have looked to push forward the development of missiles that can travel at more than five times the speed of sound and are highly manoeuvrable, which make them hard to detect and even harder to intercept. Last year, the Pentagon said a Chinese hypersonic missile had circled the planet. Beijing said its test was not of a hypersonic missile, but part of a “routine spacecraft experiment”. The US and Australia already have a hypersonic weapons programme. The Pentagon’s hi-tech research arm says it recently completed a free-flight test of an aircraft-launched hypersonic missile, although the US Air Force says operational capability has been delayed by a year. Chinese foreign ministry spokesman Zhao Lijian said the Aukus plan not only increased the risk of nuclear proliferation, but also further intensified the arms race in the Asia-Pacific. Escalation of new weapons capabilities, especially evasion of detection, may be seen as mutual deterrence by some, but does not reflect most people’s yearning for peace. Rather, it generates fear and uncertainty that can lead to instability. This is not a direction in which the world should be moving without deep reflection on the risks and benefits.