How accurate are those early numbers compared to what has been returned so far? Was Alaska one of the states with a Dem advantage in early voting?
Alaska's early vote has always trended Democratic in recent cycles. So much so that it makes precinct-level maps inaccurate because the early vote is only broken down by House District, not precinct.
One thing to keep in mind is that at least in the primary, late early votes (from the days immediately before the election) aren't counted on election night. So if Sullivan and Begich are close to tied on election night, Begich will likely win.
Also I've heard that the ballots sent in from the rural Native areas could take 4-5 extra days to count.
