In all-important Colorado, counties to watch as votes are tallied

Reporting from Denver —  As polls close in Colorado, all eyes will be on two suburban Denver counties that often swing statewide elections.

Jefferson and Arapahoe counties demonstrate the increasingly large and somewhat unpredictable impact unaffiliated voters have on Colorado elections. The state is divided almost evenly into thirds between Democrats, Republicans and unaffiliated voters.

“The saying in Colorado politics since as long as I’ve been paying attention has been, ‘as goes Jeffco, so goes Colorado.’ So far, and it’s important to note that it’s early, I’d say it’s going Republican,” Curtis Hubbard, a partner at the Democratic consulting firm OnSight Public Affairs, said in an email exchange.

In 2010, Democrat Michael Bennet received 47% of the vote in Jefferson County and Republican Ken Buck 44%. More than 8% of voters cast their ballots for some other candidate four years ago.

“Two things we’ll be watching in Jeffco tonight: how unaffiliateds break, and the percentage of votes cast for third- or minor-party candidates,” Hubbard said.

He added, “The former is considerably more important this year than in years past, as unaffiliated voters now make up the largest block, 37%, of Jeffco voters. Republicans follow at 32% and Dems trail at 29.5%. Consider that in 2010, Republicans accounted for more than 35% of the Jeffco electorate and Dems and unaffiliated voters accounted for 32% each. “

Arapahoe County has been one of the keys to the winning streak Democrats have been on in statewide races for more than a decade, and its performance tonight will be the true measure of whether Republicans have a strong ground game.

“They invested heavily there to protect incumbent Rep. Mike Coffman (R-Aurora), but also to stem their losses. Arapahoe County has become friendlier to Democrats as it has been beset by an influx of newcomers and minorities,” said Hubbard.

Twitter: @kurtisalee