“Iran has a peculiar relationship with the Taliban,” says David Patrikarakos in The Spectator. Iran is Shia and the Taliban Sunni, for one thing, so “each considers the other to be deviant”. And they nearly went to war in 1998 after 11 Iranian diplomats were killed by what the Taliban called “renegade forces”. But Iran was happy to shelter al-Qaeda leaders in Tehran and has long sponsored Taliban groups in Afghanistan.
The key to their on-off relationship is water – currently in such short supply in Iran that the ruling mullahs fear revolution. The Helmand River flows from Afghanistan into Iran, and former Afghan president Ashraf Ghani inaugurated a dam on it in March. He declared that the Iranians would have to hand over fuel if they wanted the water to flow. It’s “no coincidence” that the city nearest the dam was one of the first targeted by the Taliban – and there are rumours that the militants’ first action was to turn on the taps for their neighbours. Iran seems to be the “immediate winner of the Taliban takeover” – just as one theocratic regime takes power, the existential peril of another is washed away.