The other day, the Rove-founded American Crossroads went up with a major ad buy for North Carolina GOP Senate candidate Thom Tillis. The ad claimed Tillis has “the conservative guts to replace Obamacare with honest health care reforms.”

But the ad didn’t use the word “repeal,” and this drew a sharp attack from one of Tillis’ conservative primary rivals, Greg Brannon, who had already been pillorying Tillis as soft on Obamacare because he has voiced support for general goals such as ending discrimination against preexisting conditions. Brannon scoffed that the ad “makes no mention of repealing Obamacare, which would take real guts.”

There’s no way anyone could take that attack seriously, right? Well, now the Raleigh News and Observer reports that Crossroads has tweaked the message in the ad, in what looks like a response to the criticism. In the new version, the word “repeal” does make an appearance! It says Tillis is “a fiscal conservative with the guts to repeal and replace Obamacare”:

The new ad no longer says even that Tillis would replace the law with “honest health care reforms,” instead leaving it at just “repeal and replace Obamacare.”

It seems impossible to believe that vowing to replace the law with “honest health care reforms” could be deemed as too soft on Obamacare. But, whatever the reason for cutting that line, it is worth noting that Tillis has been getting attacked from the right for talking in even the most general terms about how he would replace the law. In a recent radio interview, Tillis talked vaguely about doing something or other that might offer some of the same sort of protections Obamacare does. This alone got him clobbered as a pro-Obamacare squish, just as the Crossroads ad vowing to replace the law with “honest health care reforms” did.

So “repeal and replace with something that would do the popular stuff in Obamacare without all that #Obummer tyranny” doesn’t work. But neither does just “repeal”; after all, none other than Crossroads-founder Karl Rove has warned that repeal alone is a political loser. So that leaves only “repeal and replace,” full stop, without even hinting at what “replace” might be. That last imperative appears increasingly central to making “repeal and replace” workable.

Obamacare is supposedly hated by everyone in the country, but coming up with just the right way to promise to rescue America from this monstrosity is proving a lot tougher than some folks expected.

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