The United States has pulled out because it was in Afghanistan for wrong reasons in the first place. The US retroactively justified its invasion with false confessions extracted by torturing the prisoners they took. They installed a ruthless drug lord’s brother-in-law as President. Faking a vaccine programme to collect biometric samples couldn’t have gained them much trust with the locals either. If they were trying to make Afghanistan a better place, well, maybe they should have subcontracted the task to China like they do everything else.