I don’t understand how they know if a ballot is Republican or Democrat without counting the votes and reporting the total. How do they know?
Party registration?
They know the party registration according to the state rolls.
They literally check off each returned absentee ballot and the campaigns are each allowed to keep a record.
This way they don’t have to keep bugging people who have already voted.
Same concept is applied on the actual election day.
Romney GOTV is VERY impressive this year.