North Carolina remains close, with Mitt Romney leading by about two percentage points statewide, or 60,000 votes, with half of the vote counted.
Almost all of Mr. Romney’s advantage can be explained by one county, Wake County, in North Carolina’s Research Triangle. President Obama won it by 64,000 votes in 2008. This year, Mr. Romney leads by 2,000 votes so far.
— Nate Silver
One county accounts for nearly all of Romney's advantage? How is this even possible?