There is a serious, calm and thoughtful discussion to be had about the western democracies’ future security and economic relationship with China, and it is under way in Washington and European capitals. Judging by her confrontational, attention-seeking speech in Tokyo today, Britain’s disgraced former prime minister Liz Truss is not part of it. Truss, short of new ideas and insights, has defaulted to crowd-pleasing, hawkish positions that appear principally designed to facilitate a domestic political comeback at Rishi Sunak’s expense. A “totalitarian” China, she says, poses a global threat to the “free world”. Britain should help rally regional countries against Beijing by building a “Pacific defence alliance” and an “economic Nato”. Truss also calls on G7 states, which will meet in Hiroshima in May, to prepare to impose tough sanctions on China if it further escalates its military intimidation of Taiwan. The self-governing island should be admitted to international organisations from which it is currently excluded, she says – a red rag to Beijing. This stance echoed her previous, provocative call for Britain to supply weapons direct to Taipei. Truss is right to suggest relations with China are at a critical point, illustrated by the absurdly hyped flap in the US that accompanied the shooting down of a Chinese surveillance balloon. But her proposals, if actively pursued, could intensify east-west tensions, deepen the divide and boost Russia’s attempts to ally itself with Beijing – while doing little or nothing to enhance international security. Her Tokyo speech raises two broader questions: is Truss truly looking for workable ways to mitigate the aggressive posture of China’s president, Xi Jinping, or is she just posturing for hard-right, anti-China audiences in Westminster and Washington? Her position, including on the selective decoupling of economic relations, undercuts Sunak, who, like Joe Biden, has declined to classify China as a “threat”. Second, does Truss truly believe that Britain is still a global power with the political will, financial wherewithal and military firepower to intervene effectively in dangerous geopolitical crises thousands of miles from its shores? If so, she is truly delusional. Alone and adrift in a post-Brexit vacuum she helped create, Britain’s ability to influence world events is diminishing rapidly. The defence and security of Europe, of which it is a part, and not the Asia-Pacific region, is the UK’s primary strategic concern. Politically, she cannot admit that axiomatic fact. Empty threats do not make good foreign policy – and we have been here before. In her Mansion House speech last year, shortly after the invasion of Ukraine, Truss insisted Russian troops must be forced back to pre-2014 borders – meaning expelled from Crimea and all of Donbas. “We are going to keep going further and faster to push Russia out of the whole of Ukraine,” she declared. You and whose army, Liz? Did she mean UK forces should launch a ground war against Russia? The Kremlin certainly thought so. Truss has hit repeat play in Tokyo, proving again that loose talk costs other people’s lives. There is no doubt Xi’s threats to subjugate Taiwan by force, his bullying of neighbours such as the Philippines, his colonisation of the South China Sea and his criminal treatment of the Uyghur and Tibetan peoples are shocking and alarming. But it is likewise clear, or should be, that Xi, despite his domestic problems, will not be deterred by a former colonial power with blood on its hands that poses no credible kinetic or economic challenge. The danger, instead, is that he may double down – with Taiwan in his gunsights. A US general recently predicted war within two years – and that was before the spy balloon went up. Yet what does calamity Liz do? She jumps in rhetorically with both feet, cliches flying. She can expect little support from the Biden administration. Likewise, Japan’s leaders may be privately appalled, though too polite to say so. Like Taiwan’s savvy president, Tsai Ing-wen, they prepare for the worst – and meantime try to manage the China relationship, not blow it up. Taking on China is not like taking on Russia. Vladimir Putin’s empire is built of straw. It will implode eventually, as happened to the Soviet Union in 1989-91. But China is too big to foil. Interdependence runs too deep, economic ties are too mutually valuable and shared challenges such as the climate emergency and nuclear proliferation are too pressing for the west to attempt to contain, let alone halt China’s rise. The western democracies have no sensible choice other than to continue to argue for their views and stand up for their values, issue by issue, while strengthening alliances, maintaining lines of communication and waiting for Beijing to modify its more objectionable behaviours, as Xi has recently started to do. Truss, with her siren calls, is digging the trenches of a second cold war. It’s a war Britain and the west cannot win – and should not fight. Simon Tisdall is a foreign affairs commentator and former Guardian foreign editor