The Aukus defence deal between Britain, the US and Australia grows murkier by the day. Essentially it is the outcome of an industrial dispute over who will build eight submarines for the Australian military. Australia ordered £48bn-worth of diesel-powered ones from France and then changed its mind, reneging on the deal. It now wants nuclear-powered ones from the US and Britain. Crewed submarines are approaching obsolescence, near useless in an age of “transparent” oceans and underwater drones. Like tanks, they drip with cost, inefficiency and a craving to fight outdated wars. But defence contracts have a corporate and political existence that transcends utility. If Australia seriously thinks China is a threat, it might as well have some new gold-plated weapons ready. However, this particular equipment contract appears to have morphed into a new military alliance in the Asia-Pacific region. Johnson’s defence adviser, Stephen Lovegrove, declares it to be “a profound strategic shift”. Unless Downing Street is clueless, it was clearly intended to enrage China, which it duly has, as well as humiliate France, which it also has. Boris Johnson protested that it was “not adversarial” toward China, but, when Theresa May asked if he seriously envisaged war over Taiwan, he refused to say no. “The United Kingdom remains determined to defend international law and that is … the strong advice we would give to the government in Beijing.” Is he just playing with words? In July he sent an aircraft carrier near a disputed region in the South China Sea, prompting warnings from Beijing. This would be merely a mouse trying to roar, were vast sums of public money not involved in sustaining Johnson’s vanity. Pompous remarks made for political effect, like sudden alliances and needless snubs, have consequences. Western defence interests born of the cold war refused to let Nato redefine its purpose in the 1990s, with the demise of the Soviet Union. Which is how Britain got sucked into Afghanistan and Iraq, ostensibly to protect the US from the new threat of terrorism. High rhetoric and military chest-beating likewise fuelled the preliminaries to the first world war. Britain has no conceivable reason for adopting an aggressive position in the Pacific. It is all arcane post-imperial nostalgia. If the US is mad enough to return to war in south-east Asia over Taiwan, it is nothing to do with Britain, any more than Vietnam was. France, too, claims concern for its “citizens” in the Pacific. Europe’s second-rank states seem unable ever to let go of their empires. China’s emergence as a world economic power in the past quarter-century has been a politico-economic miracle. It was achieved by marrying the disciplines of capitalism to those of dictatorship. The west may not like some of its manifestations and is free to say so. They are not the west’s business. China does not fall under the west’s sovereignty. With its newly powerful status, China has embraced military aggrandisement, sensitivity to criticism and a regional sphere of influence, all syndromes that should be familiar to the US. Time alone will tell where this leads. But for the west now to open a cold war with China must be beyond stupid, and for Britain especially fatuous. So-called western diplomacy is currently a disaster area. It has failed to adjust to post-communist Russia, and its handling of the Muslim world has been ham-fisted and tragic. In Afghanistan the most expensive armies in the world have been sent packing by a fistful of AK-47s. It is half a century since Harold Wilson formally withdrew Britain from “east of Suez”. Johnson clearly aches to return, to prove that he can somehow punch above his weight and put Britain back on the world stage after Brexit. Foreign policy so vacuously formulated is reckless. British diplomacy should now be concentrated on Europe, overwhelmingly so. One thing Brexit did not alter was geography. Simon Jenkins is a Guardian columnist