The Tampa Bay Times reports that Alex Sink, the Dem candidate in the special election in Florida’s 13th District, is out with an interesting new ad defending her support for the Affordable Care Act and ripping opponent David Jolly’s embrace of repeal:

The ad is notable because it lays out the consequences of repeal, flatly stating that it would mean going back to the old system.

“Jolly would go back to letting insurance companies deny coverage,” a narrator says. “His plan would even force seniors to pay thousands more for prescription drugs.” Sink then says:

“We can’t go back to letting insurance companies do whatever they want. Instead of repealing the health care law, we need to keep what’s right and fix what’s wrong. I’ll work with Republicans and Democrats for health care that’s affordable — and works for us.”

A Democrat familiar with internal polling in this swing district tells me the ad is partly aimed at Dem-leaning voters who might be somewhat less inclined to turn out, but might benefit from the law, like lower income women — single women, waitress moms — and older Dem-leaning voters who enjoy provisions such as the closing of the Medicare “donut hole.”

This comes as Sink has been pummeled by multiple Obamacare ads — from the NRCC, the U.S. Chamber of Commerce, and Jolly — all of which repeat variations of the same talking point: Sink supports Obamacare, even though it has caused people to lose their coverage. Sink’s new ad tests the Dem response, i.e., the now-familiar “keep and fix” message, and combines it with a more direct attack on repeal than we’ve seen from other Dems, particularly those in red states.

While pundits have focused relentlessly on red state Dems distancing themselves from the law, it’s not surprising that they’re not embracing the law in Republican in states where Obama is so unpopular. The other side of the story — which tends to get far less attention — are ads like this one from Sink, which is premised on the belief that even if Obamacare is unpopular, repeal is also unpopular with the middle of the country, where the GOP base’s seething rage at the law and everything it symbolizes just doesn’t really exist.

The outcome of this race will be widely interpreted as a clue to the political environment this fall. But that stuff is always overstated. Whoever wins, I’d caution against reading too much into it. One thing that’s likely, however: if Sink wins while embracing the ACA in this fashion, it won’t diminish the absolutely certainty among Republicans that the law’s ongoing collapse will deliver a glorious 2014 triumph — certainty that has only been hardened by the CBO report, even though it actually found the law on track to come close to its targets — and that no other possible outcome is worth entertaining.

As the law’s disastrous launch fades from memory, and as enrollment continues to mount — provided the Next Big Obamacare Disaster doesn’t materialize — you could see more Dems gain the confidence to embrace a message such as this one a bit more directly.

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