Greenwood Village, Colorado (CNN) - Nearly six hours after polls closed in Colorado, the campaigns in the Senate race called it a night with no winner and no concessions.
Republican Ken Buck and Democratic Sen. Michael Bennet are locked in a race that is too close to call. With 81 percent of the vote counted, Buck holds a slight lead over Bennet, 49 percent to 47 percent.
Neither candidate addressed supporters Tuesday night. Instead, campaign officials spoke at their respective headquarters after it became clear that no more votes would be processed for the night in some counties.
At Buck headquarters, campaign adviser Walt Klein told the crowd, "maybe in the next day or so or next twelve hours" it will all get sorted out. The Buck campaign says when all the votes are counted, Buck will emerge as the winner.
Democrats are saying the same thing.
"We believe that when every single vote is counted Michael will come out on top,"
Bennet spokesman Trevor Kincaid said.
But with the race being so tight, there is the potential for a recount. Under Colorado law, if the margin of victory is half of one percentage point, a recount would be automatically triggered.
Lawyers for both parties have been bracing for the possibility.