In the still-to-be-decided race for a US Senate seat in Minnesota, an Associated Press analysis of votes indicates that most ballots lacking a Senate vote were cast in counties won by Democrat Barack Obama.
The 25,000-vote difference in presidential and Senate race tallies could be due to different reasons - either some of the voters might have intentionally bypassed the Senate race, or others might have mismarked their ballot, or optical scanning machines might have misread them.
As such, a recount of the votes will begin November 19, and will use manual inspection to detect such ballots.