During his brief time in the Idaho House of Representatives, Scott Bedke often stopped to admire a photograph from the state's 1899 legislative session. In the photo were lawmakers from four distinct parties, along with a handful of unaffiliated candidates. "That was a period just like now," Mr. Bedke said. "People were fed up with the party system and looking for something different."

Today, he's part of an effort to bring that same kind of something different to Idaho and other parts of the West. Mr. Bedke, an unaffiliated candidate for Idaho Senate, is among a wave of independent challengers to entrenched Republican incumbents or heirs apparent in red states. In Idaho, where unaffiliated voters outnumber Democrats 2 to 1, Mr. Bedke is the more prominent and moneyed of two independents challenging the incumbent, Jim Patrick. Independents also are running for Idaho governor, both of the state's U.S. House seats and 12 state legislative seats. Next door in Wyoming, another independent, Rex Rammell, is running for the Senate as an independent, as is Greg Brower in Nevada and Tim Clements in Arizona. Another, Paul Leavitt, is running for Idaho's lone House seat. All those candidacies say a lot about the state of the Democratic Party west of the Mississippi, excluding what's known, affectionately or not, as "the left coast" — Utah, Colorado and New Mexico. Some of these independents are long shots, none of them are favored, but they all figure they are better off than a Democrat would be.

"We've got a brand problem in places like Idaho and Wyoming," said State Democratic Party chairman, Luke Malek, which includes Idaho and its fast-growing suburbs. "Having a 'D' next to your name makes winning unlikely, if not impossible."

Many Democratic leaders don't love the trend. State Democratic Party chairwoman, Dorothy Moon, said progressives and moderates could not "expect independents to save us."

Since 1990, only five states have elected a governor running outside of the Democratic and Republican parties. Two senators — Kyrsten Sinema of Arizona and Angus King of Maine — are independent; both caucus with the Democrats. No current Idaho representative was elected as an independent, though one, Russ Fulcher of Idaho, became independent after Democrats redistricted his seat to make it unfriendly to his old Republican Party. He still caucuses with Republicans. But critics of western Republicans say something must be done to challenge unchecked one-party rule and policies that have gone too far.