“Thom Tillis has a proven record of fighting against Obamacare. Tillis stopped Obamacare’s Medicaid expansion cold. It’s not happening in North Carolina, and it’s because of Thom Tillis.”

The expected GOP Senate nominee for North Carolina is boasting, in effect, that he is the sole reason 500,000 people in the state he would represent will not get health coverage under the Medicaid expansion. This quote comes from a radio ad Tillis ran this week in the GOP Senate primary.

This will be another interesting test of how the actual GOP position on Obamacare — get rid of it and its benefits for millions — will play politically, as the law’s implementation has made it harder and harder for Republicans to campaign on abstract notions of “repeal and replace.” It’s slowly sinking in with the national press that Democrats are not uniformly running away from the law, and that the GOP repeal stance just might have problems of its own.

The backstory: Tillis, who has to avoid a primary runoff, has been under fire from conservative rivals as soft on Obamacare, because he suggested the law’s general goals might not be uniformly awful and even said Obamacare is a “great idea that can’t be paid for.” Senator Kay Hagan’s campaign then ran a radio ad tweaking Tillis over that quote, in a move observers speculated was designed to hurt him among GOP primary voters. Now Tillis is up with the radio spot — flagged by North Carolina Dems — reinforcing his anti-Obamacare cred:

Interestingly, the ad describes blocking the Medicaid expansion — which would expand coverage to half a million people — as a key part of the “conservative revolution” Tillis helped engineer in Raleigh.

The Hagan campaign will make this a part of their case against Tillis, using his opposition to the Medicaid expansion to argue that Tillis’ “conservative revolution” is terrible for the middle class.

“Tillis will have to answer for his bragging about rejecting health care for 500,000 North Carolinans, a move that also cost health care providers millions, in particular those in rural areas,” Hagan spokesperson Sadie Weiner emails. “Tillis has shown time and again that he will push a special interest agenda at the expense of middle class families, whether it’s rejecting health care for 500,000 North Carolinians or handing out tax cuts to the wealthy while teachers were force to go another year without a pay raise.”

This week’s New York Times poll, by the way, found that North Carolinians support expanding Medicaid by 54-36. Also noteworthy: The “Moral Mondays” movement that has arisen in the state was partly spurred by the decision not to opt in to the Medicaid expansion. And so, if one of the core challenges Dems face this fall is getting out their core groups, citing the Medicaid expansion might be one part of the argument designed to galvanize them.

More broadly, if Dems can use Tillis’ boasts about blocking the Medicaid expansion for half a million people — apparently a big plus in a GOP primary — as part of a broader general election case that the conservative economic agenda is bad for the middle class, this would be another way the politics of Obamacare are proving to be more complicated than the tidy GOP political narrative has it. Dems are going to go hard at Republicans over the Medicaid expansion, even in some red states. And the politics of this are murky for Republicans: Note that GOP Senate candidates Scott Brown, Tom Cotton, and Terri Lynn Land have all refused to take a position on it.

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.