As staffers at Mark Dayton's campaign headquarters awaited returns shortly before 8 p.m., one question loomed: how many people turned out to vote?

One persistent theory is that Dayton, with big name recognition, might especially benefit from a big turnout. The Dayton campaign took steps earlier this summer to make sure their voters turned out -- even if they were away from home on vacation and couldn't vote in person at their neighborhood polls.

"We really pushed our voters to vote absentee," said spokeswoman Katie Tinucci.

She found hope in the over 30,000 absentee ballots that were cast in this race, a sharp increase from previous elections.

"We're hoping a lot of those are for Mark," she said, though quickly acknowledged that the surge of absentee voters might not mean a large overall turnout in the primary. "It's possible it is just regular primary voters who would have voted today but were out of town."