So, it turns out that the ECC threw out nearly 1/3 of the ballots cast for Karzai, and the US government is saying that it cannot make a decision about more troops until the matter is resolved.
My guess is that Karzai will accept a runoff, and that he will probably win, as he has extensive support from the largest ethnic group in Afghanistan, as well as a bureaucracy that will be firmly supporting him in the balloting.