Her challengers contend voters are fed up with the status quo.
Davis accused Capito of double-talk when it comes to money in politics and bipartisan cooperation, and he derided her for creating "a false dichotomy" by pitting the environment against jobs.
"We need both. And we can have both," Davis said. "We're a smart people, we're a creative people, and we're a rich society in more ways than monetary. We're rich in our creativity and ability to cooperate and not see the other side as the enemy."
On his website, though, Davis offers views that could cost him the support of the party's most conservative voters.
He blames the tea party for bringing the legislative process "to a screeching halt." He defends President Obama against those who question his citizenship, calling him a good person who "has the best interests of our country at heart." And Davis says former President George W. Bush took the country "to the brink of ruin," launched two "senseless" wars and allowed big banks to "run wild and ruin our economy."
Both parties, Davis argues, are unable to face the core problem: Government favors corporations and the wealthy.
So why not run as a third-party candidate?
Voters, he said, won't elect one.
"Not today," Davis said, "and not in West Virginia."
Miller also risks alienating voters -- perhaps at the other end of the Republican spectrum -- by putting his faith front and center. He's pledged to apply the same formula to every vote: It must comport with what his constituents want, what the Constitution allows and what the word of God commands.
As an example, Miller pointed to a bill that would have let people borrow more money than their homes are worth. The Legislature had constitutional authority to act, he said. His constituents supported it.
"But I don't believe God supports it," Miller says. "God's word is very clear about how you borrow money, that it should be very limited and that you should think very carefully about what you're doing. And so that is a clear prohibition in Scripture."
Miller, who has not been outspoken about his faith in past races, said he rededicated his life to God in 2009 and contemplated leaving politics when he saw "too much worshipping of the office."
"My faith is the driving part of who I am now, and the most important part of me in public service," he said.
"There will be people offended by that," he said, "but I would rather offend people for my belief in Christ and my lord and savior than for any other issue."