Voters strongly supported Ballot Measure 2A, a three-year, .3 percent tax projected to provide $27.6 million for cultural and public safety projects.
"[E]ven with a handful of counties still reporting, there just aren't enough options to get us across the finish line," Beauprez said Wednesday afternoon.
Voters across the state decided several issues -- from marijuana in Manitou Springs to a tax for pre-schools in Denver.
Colorado voters rejected three of four statewide ballot measures on Election Day.
The national Democratic and Republican parties poured millions into the contest, one of the most expensive races in state history.
Knocking on doors in Colorado, NPR's Steve Inskeep reports that the GOP could be close to winning the Senate without changing the political positions that are said to endanger the party's future.