Republicans stuck in an 'electoral cul-de-sac?' That's how it looks near Denver

"I'm pro-Hillary and anti-Trump," says Patti Dub, whose husband is of Canadian heritage.

"My decision is to vote for Hillary," says Kimberly Thebeau.

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In two hours, all except one of those20 or so voters said they pickedClinton, the Democratic candidate locked in a battle with Republican presidential hopeful Donald Trump.

For Republicans, this is bad news. Really bad. Because what's happening here is slowly happening in suburbs across the United States.

Twenty years ago, Colorado was a red state. And this suburb of Arapahoe Countyjust half an hour outside Denver was just as Republican as the rural outskirts.

More diversity

"The southern ring counties in Colorado used to be the most conservative in the state," says TonyRobinson, political science chair at the University of Colorado Denver.

"In the last two election cycles, Arapahoe County has voted Republican at the presidential level."

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So what happened?

First, Colorado started becoming younger, more educatedand more diverse. It began in Denver, then the ripple slowly spread.

"They're moving into the suburbs," says Robinson, "and when they do they change those voting patterns. And the suburbs are no longer reliably red."

Fifteen years ago, Charles Twitty was the only person of colour in his neighbourhood. Not anymore.

"Colorado, especially Arapahoe County, is becoming a melting pot," he says as he drops off his vote for Clintonat the ballot box.

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The problem is, Robinson says, the Republicans' message doesn't appeal to these new suburban voters.

"Donald Trump represents the old notion, that kind of old, white, male voters are the centreof American politics, and he isspeaking to them. And that once was true in a county like Arapaho County. It is no longer true."

Some Colorado politicians are trying to adapt. Mike Coffman,theRepublican congressman who represents Arapahoe County, cut an ad dumping onTrump.

Latinos aren't buying it

"Honestly," he says in the ad, "I don't care for him much."

Then Coffman released an adin Spanish.

But Arapahoe County resident Luiz Castillo says mostLatinos he knows aren't buying itand they're coming out in droves to vote for Democrats.

"This year they know it's very important for them," Castillo says. "They know that we get very affected if we don't go out there and vote."

These demographic changes aren't just happening in Colorado. Robinson says there's a similar patterninGeorgia, Virginia and Pennsylvania.

AndColorado's demographic transition, he says, "is leading the way that America is changing in general."

The other reason Trump signs here are a rare sight: Republican candidates have become too right wing for many suburban Republicans.

Matthew Dionne says the partyexpectshim to vote for these more extreme Republicans simply out of party loyalty.

"We're being dragged kicking and screaming to vote for whatever candidate they've dragged forward for us."

Now, for the first time, he says he's not voting Republican.

And these trends are bigger than Trump.

Robinson saysidentification with the Republican party in Colorado has gone down five per cent in the last 10 years. Across the U.S., the Republicans have lost most major urban areas.

"The Republican party right now is in an electoralcul-de-sac," Robinsonsays. "A dead end. Any party that is continuing to build its base on 70 per cent of its voters aswhite males has no future."

The electoral math may comedown to this equation: win back Arapahoe County, win back the White House.

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