State Rep. Cynthia Davis may be getting a lot of attention over her bid to unseat a fellow Republican, state Sen. Scott Rupp -- but that doesn't mean the senator is worried.

"I'm not overly concerned about her candidacy," said Rupp, R- Wentzville. He added that Davis "is trying hard to find reasons to back up her claims" for why voters should toss out Rupp.

Chief among them, says Davis, is that Rupp in her mind is no conservative.

"I'm a conservative and I'm fed up with people who run as Republicans and claim to be conservative, when they are really moderates," Davis said.

That moderate crowd, she added, includes Rupp.

Rupp, 36, is a banker. Davis, 50, notes that she's the mother of seven children.

Their contest in this August's Republican primary promises to among the hottest -- and, predicts Davis, the nastiest -- intra-party battles of the summer. Filing for the post begins next month.

Both emphasize that they oppose abortion, support gun rights and seek to protect the state's sovereignty from federal infringement.

That said, Davis asserted that Rupp's voting record shows that he supports proposals "that expand government and bloat the budget."

As a key example, Davis cites the senator's vote last session in support of Gov. Jay Nixon's unsuccessful plan, forged with Missouri hospitals, that would have added 35,000 adults to the state's Medicaid rolls without using state tax dollars. The hospitals had agreed to pay higher fees to the state, which were to be used to leverage more federal matching funds.

The state Senate overwhelmingly approved the plan last session, but the House killed it.

Davis was among those who voted against it.

"He voted to put able-bodied adults back on Medicaid," Davis said of Rupp, adding that she viewed the proposal as an effort to expand the state's welfare rolls. "It was Gov. Jay Nixon and the Senate against the House."

That's not how Rupp saw it. "The whole entire Senate supported that," he said, largely because private funds were to be used. Rupp added that if more Missourians have some sort of insurance, even if it's Medicaid, everyone else pays less for their coverage because there are fewer uninsured to drive up rates.

Rupp said that he viewed the episode as an example of how he has focused on "being more prudent with taxpayer dollars."

As for Davis, the senator asserted that "she has not accomplished anything in over seven years" in the state House.

Rupp also has jabbed at Davis' national notoriety -- in which she was featured on comedy news shows like the "Colbert Report" -- over her comments against summer food programs for low-income children ("Hunger can be a positive motivator," Davis said) and her opposition to vaccination programs administered by the government or public schools. 

As Rupp tells it, Davis opted to challenge him after she initially asked for his endorsement if she ran for state auditor. When she didn't get state party support, he said, she decided instead to challenge him for his Senate seat.

Davis has acknowledged that her decision was influenced, in part, by the fact that this is her final year in the state House, as mandated by term limits. If she could run for re-election and remain in the House, Davis said, she'd probably do so.

But Davis adds that she's also concerned by what she views as too much camaraderie in the Senate between Republicans and Democrats. "The Senate has become a big fraternity club," she said, where members' "loyalty to each other" outweighs their partisan differences.

"You can't tell who's a Republican or Democrat," Davis complained. If she wins, she said, that will change.