While Rick Santorum won Colorado along with two other states last night, he did not win the key Colorado county of Arapahoe.
Political experts say Arapahoe has been on the winning side in nearly every presidential election of the past four decades.
That's where Mary Marks and her husband, Kenny, live. Marks says she figured Romney would win the nomination, so she gave one last vote for the candidate she calls the real conservative, Rick Santorum.
"I like that Santorum had a good showing so that he can push Romney to the right," Marks tells NPR.
Countywide, Romney won by 200 votes — or about 11 percent.
"Arapahoe County's been considered kind of a bellwether county in recent elections," said Seth Masket, a political scientist at the University of Denver.
Not too long ago, says Masket, Arapahoe was solidly Republican. But as it's become competitive, it's also become a predictor, going with the winner in presidential and gubernatorial elections.
"It usually swings pretty widely, and that's because kind of the makeup of the county. It covers a lot of ground. It both covers a very urban area, the city of Aurora, and stretches pretty far to the east into some very rural territory," said Masket.
Independents make up about 30 percent of the voter registration in the county. So Masket says moderation is the key to success — and that goes for Democrats, too.
Alfonso Nunez is a lifelong Democrat, but has voted Republican. Nunez, whose family owns a Mexican restaurant that has been in Aurora since 1970, says he hasn't made his presidential choice yet.
Nunez voted for President Obama in 2008 but isn't happy with the state of the economy. He says the president should have tackled that before going after health care.
And he's still waiting for that comprehensive immigration overhaul that, he says, Obama promised.
"There's a lot of things that go into the way I vote, unfortunately. I know I'm just one vote, but whoever I vote for is going to have to earn it," said Nunez.
Picking the moderate was exactly what Jaime Wollman did Tuesday night. She said she really wanted to vote for someone more conservative, but in the end went for Romney.
"He is the only one who has an opportunity to get independent votes," said Wollman.
But this was not a night for independent votes.
In primary caucuses that brought out just 6 percent of the state's Republicans, the desire to vote for a conservative held sway.