With about half of all votes counted, Karzai has 45.8% of the vote, a slight tick downward from his earlier lead when 35% of votes were counted. This will be a nailbiter.
The IEC chairman said that the 5th or the 6th is the date we should be eyeing for results to come in. Until then, the fraud allegations have caused confidence in the election, domestically and abroad, to plummet. If confidence can't be built back, Karzai (or whomever was involved) may have handed the Taliban their biggest victory of the war. In Kandahar province, tribal leaders are publicly accusing aides to Karzai's brother (the provincial leader of Kandahar) of shutting down polling booths and shipping in ballots from elsewhere, all marked for Karzai (these tribal leaders had decided to endorse Abdullah). Kandahar province is predominantly Pashtun; such an accusation suggests that whatever unrest may come of a Karzai victory (if, as is almost certain, it is believed to be rigged) will lead to unrest in Pashtun regions as well as elsewhere.
Things are looking bad. I can't help but worry that ISAF has created a monster. US and EU envoys are considering their response to the election results. The IEC, it appears, has the power to declare the election broken and force a run-off, which the US and EU appear to hope to persuade, should the numbers work out for Karzai.
But whether things will go better the second time is a bleak question. It appears now that Karzai is much more interested in maintaining his position than his legitimacy, and such an incentive (for a man with as much power as he has) is dangerous.