Karzai doesn’t agree with you that he is in charge of this war:
http://www.usatoday.com/news/world/2008-11-05-afghanistan-violence_N.htm
Karzai speaks for Afghan consumption, not US. He doesn’t care about US opinion, but what the Afghans think.
Being a typical lying politician, he is happy to have the US military take the blame for anything bad, although the Afghan Army will kill innocent civilians without blinking an eye...