But this time around, Kirkpatrick has a new rebuttal. Earlier this year, the Arizona GOP ruptured in civil war as one group, led by Republican Gov. Jan Brewer, teamed with Democratic legislators to expand the state's Medicaid program using federal funds from Obamacare. Both state legislators running against Kirkpatrick voted and lobbied against the Medicaid expansion in the Arizona House.

That's given Kirkpatrick an opening. Her district is rural, poorer than average, and has a large Native American population—all elements that Kirkpatrick says will make Obamacare especially positive in her region.

"Anyone who campaigns on repealing the law or opposing Medicaid expansion is really out of step with this district," Kirkpatrick said in June after the state Legislature agreed to expand the state's Medicaid program. "They just don't know the district."

Arizona state Rep. Adam Kwasman, one of the Republicans who voted against expanding Medicaid and is considering a campaign against Kirkpatrick, isn't shying away from a fight. "If she wants to defend a program like that, whoever she runs against: Bring it on," he said.

In some states, even Republican-run governments are expressing some level of buy-in on Obamacare that complicates GOP efforts to brand the law a failure and waste of funds. Take Iowa, for instance, which features a competitive, open-seat Senate race next year. Despite Republican control of the governorship, the state has compromised with the federal government to help set up its own state-based exchange. "While we have varying opinions regarding the Affordable Care Act, we have not let our differences prevent us from meeting our responsibilities and moving Iowa forward," Republican Gov. Terry Branstad wrote in a letter to Health and Human Services Secretary Kathleen Sebelius.

The friendliness of some GOP officials toward Obamacare further weakens the GOP's rhetoric. Rep. David Joyce, R-Ohio, is a top target of Democrats, and an avowed opponent of Obamacare. But his home-state governor, Republican John Kasich, endorsed expanding Medicaid there. And because Kasich is also seeking reelection in 2014, he'll likely tout his own decision to cooperate with the federal health care program even as Joyce takes aim at it.

"Will his criticism put him in the cross-hairs of Kasich, who will be also on the ballot?" said Brock McCleary, a Republican pollster. "That's a fascinating dynamic."

Republicans are convinced Obamacare will ultimately be a net positive for them in every race, even as they acknowledge its politics will vary from one to another.

Take New York, for example, where the iconic grocery chain Wegmans is an upstate staple. The company announced earlier this year it was cutting benefits for part-time workers. The news, similar examples of which can be found in most areas, is the perfect opportunity to show voters how the law is hurting their community, according to Andrea Bozek, spokeswoman for the National Republican Congressional Committee. "Anytime you can take a national issue that is increasingly unpopular and localize it for folks and show voters how it can directly impact about the pocketbook and health care, two things they care passionately about, it's a very effective tool to have," she said.