Joe Biden declares an end to “an era of major military operations to remake other countries”. A president’s job, he says, is to protect and defend the “fundamental national security interest of the United States of America”. That does not include trying to construct new nations in foreign states. Quite so. But Biden isn’t the first president to make such claims. Each of his recent predecessors won power as non-interventionists, but tried to hold on to it by waging war. Bill Clinton said America’s mission abroad was “not about fighting a war”, it was about bringing people to the peace table. He ended up bombing Iraq and Yugoslavia. At first, George Bush agreed with Clinton’s sentiment. On coming to office, Bush’s aide, Condoleezza Rice, emphasised his opposition to foreign adventures. “We don’t need to have the 82nd Airborne escorting kids to kindergarten,” she told the media. Yet the Bush doctrine had soon proclaimed an American crusade for “the expansion of freedom in all the world … with the ultimate goal of ending tyranny”. Not to be outdone, Barack Obama vowed to “pivot” foreign policy towards Asia, and be out of Afghanistan by 2011. He then surged into Afghanistan with 110,000 American troops. Donald Trump said Afghanistan was “a complete waste”. He then postponed departure for four years, leaving it up to his successor to handle. The truth is that war has the best political tunes. Tony Blair plunged into an impressive search for peace after 9/11, seeking a place on the world stage by pleading for cunning not killing. When he was overruled by Bush, Blair dramatically declared : “The kaleidoscope has been shaken, the pieces are in flux, soon they will settle again. Before they do, let us reorder this world around us.” The pomposity of his message was absurd. Trump was honest when he admitted that his instincts were to have nothing to do with overseas ventures, but that all his life he “heard that decisions are much different when you sit behind the desk in the Oval Office”. How these decisions differ matters. Decisions overseas are driven mostly by events, and this gives political leadership a new urgency, and new opportunities. For powerful states, foreign wars may begin to look good: roaring planes, falling bombs and surging armies grab headlines. The glory of guns outbids that of money. But money ultimately has more power. Generals on both sides of the Atlantic have been pleading this week for what amounts to one last push. Behind them, military, industrial, diplomatic and even charitable sectors bulge with money and have a vested interest in continued occupation. Modern government is no match for the power of Dwight Eisenhower’s military-industrial complex. Biden’s military commanders cried with one voice that they had not finished yet: 20 years of effort, employment and contracts pressured the president to remain in Afghanistan. In the latter period of the British empire – of which events in Iraq and Afghanistan offer an uncanny echo – colonies became costly, not profitable. They duly required ever-more elaborate eulogies and justifications. To Joseph Chamberlain, Lord Milner and his Round Table, colonial wars were a sacred duty of European powers. The concept of a Christian imperium was one of ethical obligation bound up with macho adventure. The colonialist Rudyard Kipling saw empire as the “white man’s burden”; in his poem of the same name, he exhorted the US to take control of the Philippines. In many ways, the occupation of Afghanistan has been Kipling for slow learners. Eisenhower first made his speech about the military-industrial complex in 1961. He warned the US of the relationship between its military and defence industry and already sensed the “acquisition of unwarranted influence” by soldiers and arms manufacturers, who were by then gaining de facto control of Congress. Eight years earlier, he had told America that “every gun that is made, every warship launched, every rocket fired, signifies … a theft from those who hunger and are not fed, cold and not clothed”. Today the objects of Eisenhower’s warnings are immeasurably more potent: the mighty host of corporations, thinktanks, research institutes and NGOs that together constitute the “defence lobby” (the “attack lobby” might be a more appropriate name). Today it beggars belief that public figures on both sides of the Atlantic can stand up and say that Afghanistan has been “worth” an estimated $2.2tn of American tax dollars and £37bn of Britain’s pounds. Where is the audit? A new book, Geopolitics for the End Time, by the Portuguese academic Bruno Maçães, foretells a political landscape profoundly altered by the climate crisis: an apocalyptic world of superpowers contending not with each other but with nature. The generalissimos of future state rivalries will be computer nerds, virologists and financial wizards. I doubt if this will diminish the appeal of military adventurism to modern politicians. But moments of bruised reflection should be seized on by those who feel these constant wars of intervention are evil and counterproductive. To watch Boris Johnson trying to big up Britain’s Afghan venture or his foreign secretary, Dominic Raab, trying to blame the military and just about anyone but himself is petty and painful. This should be compulsory viewing before any future ventures are considered. We should realise the debt owed to the House of Commons for its 2013 vote that stopped David Cameron’s reckless bid to invade Syria, although it failed to prevent his role in the devastation of Libya. Wars of intervention have become political baubles and vanity projects. They meddle in other people’s affairs, other cultures and other views on how societies should be run. They are an offence against the UN charter and the rights to self-determination. It is hard to avoid the accusations that they are racist. If we want to help other people in distress, there is a wealth of charitable causes to oblige. In almost every case, military action just makes things worse. We might hope that the US will now retreat into a period of introversion and sober reflection. It did so after defeat in Vietnam in 1975. To the recent generation of Anglo-American politicians, these wars have been a sick reprise of an old imperialist urge. They are a stupendous expenditure of lives and treasure at mind-boggling opportunity cost. They appear over. Yet even as Iraq and Afghanistan sink below the horizon, we can sense Taiwan and Ukraine stumbling into view. Will anything be learned? Simon Jenkins is a Guardian columnist