One of the key questions of this cycle has been: With the potency of anti-Obamacare attacks fading as enrollment mounts and roll-out problems are forgotten, will we reach a point where vulnerable Democrats in red state territory feel comfortable airing ads touting their support for health care reform?

In what may be the first, and certainly the most ambitious, such effort of the year, Senator Mark Pryor of Arkansas is going up with a new and emotional ad that is focused solely on presenting his vote for health reform as a positive:

The ad is backed by a significant, six-figure statewide buy, I’m told. The spot tells the story of Pryor’s own battle with cancer, and features the Senator sitting alongside his father, David Pryor:

DAVID: When Mark was diagnosed with cancer, we thought we might lose him.

MARK: My family and my faith helped me through the rough times.

DAVID: But you know what? Mark’s insurance company didn’t want to pay for the treatment that ultimately saved his life.

MARK: No one should be fighting an insurance company while you’re fighting for your life. That’s why I helped pass a law that prevents insurance companies from canceling your policy if  you get sick, or deny coverage for preexisting conditions.

The spot represents an effort to shift the debate over the law away from the land of GOP talking points where it has resided so long — in this and so many other Senate races — and back to one of the fundamental moral imperatives driving health reform, i.e., protecting the sick and vulnerable from insurance industry abuse. Republicans have long sought to dominate in the anecdote war — stressing hyper-exaggerated horror stories about canceled plans and lost coverage — while refusing to acknowledge the existence of the law’s many beneficiaries. And Dems have been perhaps not engaged on this front forcefully enough, because in places where control of the Senate will be decided, pointing to the folks gaining coverage might not be compelling to the persuadable voters Obamacare has alienated.

In this ad, Pryor engages the battle over anecdotes by citing his own. Republicans have cast Pryor’s vote for the health law — and that of most other Dem incumbents — as proof  they are little more than Obama stooges. This ad pushes back by personalizing Pryor’s vote — its implicit message is that it wasn’t for Obama but rather was born of Pryor’s own personal experience and a moral obligation he felt towards those who might one day endure the same.

It is also in keeping with the larger strategy of Pryor and other Democrats, who are emphasizing their personal ties to the state, and their families’ political legacies and brands (hence the appearance of Pryor’s father), to survive amid a difficult national environment.

Republicans will undoubtedly cast this as an acknowledgment that their attacks on Pryor over the law are working and could no longer be ignored. They’ll argue Pryor is, in desperation, using his faith and personal experience as a shield against those attacks. But this misses what’s really going on here. This ad is actually coming at a point where there are signs the anti-Obamacare fires are cooling somewhat. GOP advertising against the law has fallen off sharply, and is surprisingly low in Arkansas. The ad appears geared towards persuadable voters — particularly women — who, now that the Affordable Care Act is not quite the albatross it was a few months ago, might now be open to hearing the Democratic case for the law, straight from the candidate.

One other key nuance: Democrats believe that in many ways the law itself is baked in as a political factor. Polls have shown the public wants to move on from the Obamacare debate. And so, when Republicans attack Pryor (or other Dems) over the law, they are not introducing new information about it — voters already know Dems voted for it — but rather are citing this to make voters more receptive to their broader case, i.e., that Democratic incumbents are nothing more than rubber stamps for the larger Obama agenda. By casting his vote as a personal moral choice, Pryor seems to be trying to undercut that argument, too.

Pryor’s own brush with mortal illness, of course, makes it easier for him to personalize the issue. But still, if this ad plays well, perhaps we may see other Dems attempt something similar.

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