President Karzai has requested the US military to move out of Afghanistan by next year. He has further requested that any and all troops that remain must be confined to major bases. The Taliban has also stated that it is ending peace talks with America. Both of these are major blows to those who want to continue finding peace in the nation. The most difficult thing about the Middle East is that there are many who wish to lead, and a lot of political and religious turmoil as to what is right.
The US has tried to find a peaceful way to end the turmoil, but parties are certainly unwilling to deal with the US. There is still a vast majority who believe the issue does not involve the US. This is another reason that there are significant requests to get the military moving out of the country. NATO allies and forces are also in Afghanistan, but they are not having any more luck than the US in ending the turmoil.
President Karzai wishes to have control back of his country. This is why he has asked the military to relocate to the major bases. It is not that he does not see a need for the US to be involved, but he needs to show he is capable of keeping the hard won peace that exists. With the Taliban and other forces still providing turmoil, Karzai sees it as a way to perhaps make a deal for peace.