When Joe Biden spoke to the American people this week, he combined a stark explanation of what he felt the US’s role in the world was with a disparaging dismissal of the Afghan forces’ refusal to fight for themselves. “We gave them every tool they could need,” Biden said. “We paid their salaries, provided for the maintenance of their air force — something the Taliban doesn’t have.  The Taliban does not have an air force.  We provided close air support. We gave them every chance to determine their own future. What we could not provide them was the will to fight for that…