Attendees cheer during speech by former Secretary of State Hillary Rodham Clinton as she makes a campaign stop to promote Democrats in re-election bids in the east Denver suburb of Aurora, Colo., on Oct. 21. (David Zalubowski/AP)

— Over the next nine days, the focus in Colorado will be on the competitive Senate race between Democratic Sen. Mark Udall and his challenger, Republican Rep. Cory Gardner, and on the gubernatorial contest that pits Democratic Gov. John Hickenlooper against former Republican congressman Bob Beauprez.

The results will have immediate consequences for the balance of power in Washington and the statehouses over the next two years. But the 2016 implications will also be noteworthy. Few states with competitive contests this fall will say more about Republican opportunities to shake up the electoral map in two years than Colorado.

On the color-coded maps of America, it has been classified as purple, a swing state and key presidential battleground. But elections of the past decade, in which Democrats generally held the high ground, have suggested to some analysts that Colorado is trending to light blue.

Republicans have not won a major statewide race in Colorado since 2004, when President George W. Bush carried the state in his reelection campaign with 52 percent of the vote. Barack Obama won it with 53 percent in 2008 and carried it again in 2012 with 52 percent.

Meanwhile, Democrats won governors’ races in 2006 and 2010 and Senate races in 2008 and 2010, most by wide margins. Only Sen. Michael F. Bennet, in 2010, had a tough race, winning by a single percentage point against tea-party-backed candidate Ken Buck, whose mistakes may have cost him the race. Hickenlooper easily won in 2010, mostly because of weak and divided opposition.

Colorado election ballots are seen on a counter Oct. 17 in this photo illustration. (Rick Wilking/Reuters)

But Colorado has something of a split personality, divided urban and rural, with committed progressives and strong conservatives. No matter how the state is seen from afar, many Democrats here are cautious about labeling Colorado as a trending Democratic stronghold.

Former Democratic governor Bill Ritter Jr., who was elected in 2006 and decided not to seek a second term, says the state is an almost perfect indicator of the center of the country ideologically. Unaffiliated voters, he said, lean neither left nor right.

“I don’t think it fits into a color-coded scheme,” he said recently. “It’s a pragmatic state that is hard to couch in terms of red, purple or blue. It depends so much on the candidate and how they can resonate.”

Beauprez said he believes Colorado actually still leans slightly right of center. He cited as evidence the results of three state Senate recall elections prompted by passage in early 2013 of strict new gun laws. Two Democratic incumbents were defeated and a third stepped down. Beauprez also said the resounding defeat last year of a ballot initiative calling for a big tax increase for school funding showed “that Colorado has limits.”

Democrats say Colorado is progressive, but not liberal — a state with a libertarian Mountain West sensibility that makes it different than true Democratic presidential strongholds such as California or Massachusetts.

Coloradoans’ attitudes are progressive on many social issues — from same-sex marriage to the legalization of marijuana use. But the urban-rural split is real — as the backlash against the gun laws illustrated. Christian conservatives remain a force within the Republican Party.

On fiscal issues, attitudes are not as progressive. Coloradoans have a skeptical view of the federal government, common throughout the intermountain West. Many are sympathetic to the anti-government rhetoric of the right, and as a result there is no reflexive support for Washington.

Also striking this fall is the degree to which Obama’s popularity has declined. In the state where he triumphantly accepted his nomination in 2008, he is no longer welcome. His image among undecided voters is now net negative. Democrats say their 2016 presidential nominee will likely have to separate from Obama to appeal here.

Two structural factors have aided the Democrats’ success in Colorado over the past decade and could continue to do so in the future. One is changing demographics, the other is the strength of the party’s political infrastructure.

The Latino population remains a key part of the Democratic coalition. Hispanics now constitute 21 percent of the state’s population, up from 17 percent in 2000, and the community continues to grow. In 2012, Hispanics made up 14 percent of the electorate, and Obama carried them with an estimated 75 percent of the vote.

For young people, another key part of Obama’s winning coalition, the Denver area has become one of the most popular destinations in the country. William Frey, a demographer at the Brookings Institution, has written that, since the recession, Denver topped all other cities in net in-migration among people ages 25-34. If Democrats can continue to win the allegiance of these younger voters, that too could stymie Republican hopes for a comeback in presidential races.

Female voters made the difference in Bennet’s close reelection victory in 2010 and Udall’s near-obsessive focus on them in his race this fall underscores the central role they now play in Colorado’s politics. Further evidence of that came last week when Hillary Rodham Clinton delivered an impassioned speech about women’s rights at a Democratic rally in the Denver suburbs.

Over the past decade, Democrats have proven better than Republicans at the mechanics of campaigns. They began building a campaign infrastructure long before Obama was a candidate. But the president expanded the party’s coalition with his 2008 campaign and deepened its get-out-the-vote operations by flooding the state with volunteer organizers. Bennet capitalized on that foundation and took it farther in 2010. Democrats are counting on another strong ground operation to carry them to victory this fall.

Rob Witwer, a former Republican state legislator from the Denver suburbs, said Republicans were long outmatched in getting out the vote. “It was almost as if they [Democrats] brought a cannon to a knife fight,” he said. “The Republican infrastructure was totally ill equipped to deal with it.” But Witwer said Republicans have begun to narrow that gap this year.

One wild card in the future direction of Colorado’s politics is the new vote-by-mail system installed for the first time. All registered voters in Colorado have received ballots this fall and only need to fill them out and mail them in to cast their vote. Registered voters can still vote in person, and non-registered voters can become eligible the same day they show up at the polls.

Democrats believe this could be an valuable weapon for their candidates, now and into the future. Noting that Democrats in Washington and Oregon have solidified their strength since going to all-mail voting, David Winkler, vice president and director of research at the progressive Project New America, said, “There is a possibility that this year is the Republicans’ last stand.”

Republicans recognize the stakes this fall. Winning one or both of the contested statewide races would give them a morale boost and make Colorado a prime target in 2016. Losses likely would prompt a reevaluation of how Republican candidates must present themselves to voters here if they hope to win in the future. If Republicans cannot win here in a year when national conditions favor the GOP, they could have an even more difficult time in a presidential year.

Still, many Democrats are wary of buying into claims that Colorado is truly trending blue. Asked where Colorado is heading politically, Democratic Rep. Ed Perlmutter said, “I’ll let you know on November 5th.”