In his classic On War , the Prussian general Carl von Clausewitz sometimes uses investment as a battle analogy. Maybe that’s why, I was once told, German financial traders read him for ideas about investment strategy. He has compared committing troops to battle to making an investment, in which the commander has to decide whether he is making a limited bet or betting the ranch. Other times, instead of cutting losses (which they can afford), generals often make the mistake of what investors call “catching a falling knife”, that is, keep committing more troops (which they can’t afford), such as from the reserves, leading to a rout. I once took a small position in the fashion chain Esprit shortly after the start of the last global financial crisis. The stock just had a price collapse but it was, for a long time, the darling of the local investment community. Why millions of dollars worth of US military equipment was left in Kabul Every time it had a big fall, I bought some more. I did it repeatedly, until it became the biggest position in my portfolio. I was selling good stocks to buy Esprit shares, in a classic case of catching a falling knife. For the first time, I felt like Napoleon – at Waterloo. Today, its share price is around 80 HK cents. I can’t help but think the United States’ debacle in Afghanistan is a lot like “catching a falling knife”. After spending US$2 trillion and causing untold suffering and destruction, America has nothing to show for it after two decades. In that case, President Joe Biden , despite all the flak he has been drawing deservedly in recent weeks, was right finally to cut the losses. Still, like many investors, he couldn’t accept it was to be a total loss. In early July, he said: “The likelihood there’s going to be the Taliban overrunning everything and owning the whole country is highly unlikely.” Taliban’s divisions cast doubt on guarantee of safety for Chinese After spending almost US$1 trillion on building up the Afghan security forces and sending American soldiers to train, fight and even die alongside them, US leaders understandably couldn’t believe the Afghan army and government would just disappear into thin air. I remember once staring at my computer screen and cursing at Esprit stocks, which kept dropping. “The truth is,” Biden said in a much-criticised speech, “Afghanistan political leaders gave up and fled the country. The Afghan military gave up, sometimes without trying to fight.” Say no more, President Biden, I completely understand. It’s still your fault, though.