U.S. Rep. Cory Gardner, who is running for the U.S. Senate seat held by Democratic Senator Mark Udall, speaks at a political rally at Heritage High School, in the Denver suburb of Littleton, Colo. (Brennan Linsley/AP)
Opinion writer

It’s a warm late-October evening at a strip mall in this Denver suburb, and Sen. Mark Udall has his sleeves rolled up as he exhorts a roomful of Democratic volunteers.

“Are you ready to do democracy?” he cries. “Are you ready to get the vote out?”

Although Udall trails slightly in the polls, Colorado Democrats believe their “ground game” will put him over the top in next week’s election, just as it worked for President Obama in 2008 and 2012, and for Michael Bennet in the 2010 Senate race.

In fact, Udall told me, his get-out-the-vote operation employs twice as many volunteers as Bennet’s did and benefits from a new mail-in voting system adopted by the state’s Democratic legislature and governor. “Your mailbox is your ballot box,” he says.

That he must depend on a last-ditch turnout drive, however, is the unhappy truth for Udall.

Democrats had hoped that 2014 would be the year that once-red Colorado completed its transition to blue, and they were not wrong to suppose that conditions might favor incumbents such as Udall or Gov. John Hickenlooper (D), who is also in a close reelection contest.

Colorado’s jobless rate is only 4.7 percent, 1.2 percentage points below the national rate, and new residents, many of them blue-leaning young people or Latinos, are flocking in. Colorado is “a happening place,” as Udall told supporters in Broomfield.

What’s gone wrong? The previously divided GOP coalesced around a credible challenger to Udall: Cory Gardner, a conservative 40-year-old member of Congress from the rural eastern edge of the state. Udall then overdid attacks on Gardner’s “extreme” anti-abortion views, alienating much of his intended audience: women. The senator is also burdened by Obama’s 40 percent approval rating in Colorado.

Beyond that familiar litany of difficulties, Udall faces subtler problems. Colorado’s prosperity is relatively difficult for a Democrat to exploit. Growth reflects not only the effervescent high-tech sector in communities such as Broomfield but also a surge in natural gas and oil production — the latter of which has doubled since Udall took office, creating thousands of high-wage jobs. Environmentalists in liberal bastions such as Boulder oppose fracking, the drilling technique behind those gains, and Udall is also backed by national climate activists; so when he supports fracking he has to hedge. Gardner, the candidate of a solidly pro-fracking party, has the freedom to be more unequivocal.

There’s a reason that energy-producing states — Texas, Oklahoma, Louisiana, North Dakota — tend to be red.

Also, although Colorado is prosperous, it is not exactly stable. This “happening place” may be a little too happening for some voters. Since Udall’s term began, change — good, bad, popular, unpopular — has come fast and furious. Oil and gas wells sprouted like big steel trees across the plains. Once unimaginable, legal marijuana and same-sex marriage are now commonplace.

A madman slaughtered 12 people at an Aurora movie theater in 2012 , prompting the Democratic legislature and Hickenlooper to enact tough gun-control measures — which, in turn, prompted a mobilization of Second Amendment activists to recall two legislators who supported the laws.

The crisis in the Middle East hit home in the Denver suburbs this fall when three immigrant teenage girls from Aurora were caught on suspicion of trying to join Islamic State extremists in Syria. Now even the voting system is new.

Amid so much political, economic and social churn, candidates of all stripes struggle to identify the political center, and voters seem disinclined to form partisan attachments.

According to Floyd Ciruli, a pollster with long experience in Colorado politics, most of the 411,000 new voters who registered during Udall’s term are independents. Consequently, instead of tilting Democratic, party registration in Colorado is still evenly split, with a slight edge for Republicans among “active” voters — the kind who participate in an off-year election. Says Ciruli: “The state is still in play.” Or, as any resident of a Denver suburb will tell you: It’s one-third, one-third, one-third.

Gardner’s overt message is the standard low-tax, limited-government GOP stuff. On a lower frequency, though, the self-styled “fifth-generation Coloradan,” who boasts that he still lives in his great-grandparents’ house, communicates an alternative to turbulence.

It’s a bit counterintuitive, to be sure: If you’re not happy with the pace or direction of change, change senators. But Gardner seems to have his finger on Colorado’s pulse.

“Colorado has always been a state that’s done what it wanted to do, regardless of party label,” Gardner told me, citing a list of past senators spanning the right-left spectrum.

His sunny, vaguely nostalgic conservatism may or may not trump the Democratic ground game. For now, though, in the nation’s most bitterly contested swing state, red isn’t quite dead.

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