I have to add the obligatory - the problem is political and not to be solved by the US. So, forget nation building in Astan.

Reasoning: The Kabul government is a lousy bunch; just as the Saigon government was a lousy bunch. In both cases, their opponents are and were even lousier. The major difference between the two situations politically are the multitude of regional power centers in Astan vice only two material power centers in Vietnam.

Regards

Mike