If Andy Burnham makes Ed Miliband his Chancellor – as seems increasingly likely – then he will hole his government below the waterline before he even steps foot in Downing Street.Critics point to Miliband’s Net Zero fanaticism as reason enough to keep him away from No11. But that misses the bigger picture. Over more than a decade in frontline politics – as a minister, Labour leader and now Energy Secretary – Miliband’s record is one of repeated and consequential failure. Again and again his decisions have left Britain, and his own party, worse off. Few politicians of the past generation can claim to have done more lasting political damage.Some would reserve that verdict for Jeremy Corbyn. But they forget that it was Miliband, as Labour leader, who rewrote the party’s leadership election rules in 2014 to ensure that the arch socialist was elected as his successor. Miliband swept away Labour’s ‘electoral college’ in favour of what was sold as ‘one member, one vote’. Anyone willing to pay £3 for a party membership could register as a supporter and vote – and the hard-Left seized the opportunity. The result was Jeremy Corbyn – a man who plunged Labour into years of extremism, factionalism and an antisemitism crisis from which it took the party almost a decade to recover.If that was a monumental error of judgment, Miliband’s conduct over Syria was graver still.In the summer of 2013, evidence emerged that the country’s leader Bashar al-Assad had used chemical weapons against his own people – crossing what US President Barack Obama had set down as his ‘red line’.David Cameron sought parliamentary approval for Britain to join limited military action alongside the United States in defence of what he called the longstanding ‘international taboo’ against the use of chemical weapons. Miliband chose instead to whip Labour MPs against the Government – and the motion failed. If Andy Burnham, left, makes Ed Miliband his Chancellor, he will hole his government below the waterline before he even steps foot in No10, writes Stephen PollardNot only was it a day of shame for Britain, it had global impact. Obama feared a repeat in Congress and so backed away. Assad was thus sent a clear signal: butcher your own people with chemical weapons and the West will look the other way.Miliband’s decision to do all he could to block action against Assad is one of the most disgraceful acts of any British politician in living memory.Yet his judgement has been no surer on domestic social policy.After resigning as leader in 2015 following Labour’s most stunning defeat since 1983, Miliband – who remained as a backbencher – started a smug and self-satisfied podcast, Reasons To Be Cheerful.In one 2017 episode, he enthusiastically promoted the arguments of the trans activist movement. He dismissed critics of self-identification as ‘bonkers’ and gave an uncritical platform to the now notorious Dr Helen Webberley, whose private clinic prescribed hormones to children and whose husband has since been struck off the medical register. It’s a clear illustration of Miliband’s approach to government: ideology first, practicality second.Which brings me back to Miliband’s deranged obsession with Net Zero – which has saddled Britain with some of the highest energy prices in the world while doing little to alter the trajectory of global emissions. Britain today accounts for roughly 0.8 per cent of the world’s carbon emissions. Yet Miliband has effectively closed the door on new North Sea oil and gas exploration at a time of acute geopolitical uncertainty, despite his own plan to decarbonise the National Grid by 2030 requiring (on Miliband’s own calculations) gas still to supply 5 per cent of all power. Meanwhile, Norway continues to exploit its oil and gas reserves, earning tens of billions in revenues while strengthening its energy security.Miliband’s flagship ambition of delivering a clean power system by 2030 is already effectively dead. To meet the target, 4.6GW of solar energy must be installed annually; in 2025 it was just 2.8GW – leaving the programme already 3.7GW short of where it needed to be by the end of last year. But the cost remains eye-watering. The climate change committee estimates annual investment in the green transition will rise from around £15billion this year to more than £30billion by the end of the decade. Miliband’s decision to stand against his brother David, right, for the Labour leadership in 2010 showed the ease with which he is willing to betray anyone Few politicians of the past generation can claim to have done more lasting political damage. Some would reserve that verdict for Jeremy CorbynMiliband has been willing to sacrifice affordability, competitiveness and energy security in pursuit of targets that increasingly appear unattainable on his own timetable.Which is why Burnham’s choice of chancellor matters so much.A Chancellor is more than a finance minister. It is an appointment that tells voters what a Prime Minister values, whom he trusts and how he intends to govern.For many people, Miliband’s decision to stand against his brother David for the Labour leadership in 2010 showed the ease with which he is willing to betray anyone if it suits him. Keir Starmer has now learned that lesson the hard way. After years of backing Miliband’s costly Net Zero agenda despite mounting economic concerns, Starmer found Miliband among the first Cabinet ministers reportedly urging him to stand aside, while making little secret of his support for Andy Burnham (presumably in pursuit of the job of Chancellor).How ironic that as Ed Miliband manoeuvres for one of the great offices of state once again, David is being widely touted as returning to the role of Foreign Secretary – the job he held when he was last in government under Gordon Brown.If Andy Burnham decides that Ed Miliband is both trustworthy and competent enough to manage the nation’s finances, he will not simply be making a personnel decision. He will be endorsing a political record marked by abject failure at home and abroad – and asking the country to believe that this time, somehow, the outcome will be different.