Explainer: What happens now that US troops have left Afghanistan?

For the first time since 2001, there are no American troops in Afghanistan after the United States completed the evacuation of most of its citizens and thousands of at-risk Afghans.

More than 114,000 people have been airlifted from Kabul airport in the past two weeks as part of the US effort.

But the end of the US military involvement in Afghanistan raises a new set of...