DiA downgrades the Afghan leader:
In late 2001 there were two powerful forces facing each other in Afghanistan: the mainly Pashtun Taliban, and the mainly Tajik and Uzbek Northern Alliance. But America wanted to unite the country, so, as usual, we went looking for a "third force". Hamid Karzai fit the bill because he was ethnically Pashtun but anti-Taliban (and foreign-educated and urbane). But for the same reasons that he didn't fall into either of the two main camps, Mr Karzai was weak. He wasn't Taliban, but he wasn't really Northern Alliance. He was "untainted" only because he didn't have his own army. And this is always the problem with third forces. If they were strong, they wouldn't be the third force; they'd be one of the first two forces...
It would be entirely possible for America to mount a COIN campaign in support of our favourite Afghan strongman. But in Hamid Karzai, we didn't pick our favourite strongman. We picked our favourite weakman. That's why we're in trouble.