Biden starts off seeming a little in the weeds, but ultimately handles an Afghanistan question pretty well.
Sanders hits him on Iraq, then scores points (with me, anyway) by admitting that he made a mistake in supporting a continued presence in Afghanistan.
Buttigieg asked about withdrawal, and delivers and answer that might have come from anyone over the last two decades—we need to get out, but get out well. But he earns some credit for talking about the replacement of the AUMF.