Aaron Blake makes a great point about the fading of Obamacare as the top issue in the 2014 elections: “As an electoral wedge issue, it has certainly lost its luster.”

The evidence is in a new George Washington University poll of likely voters:

Of the 70 percent who said the country was off on the wrong track, just 5 percent offered a reason having to do with Obamacare. In other words, only about 3.5 percent of all Americans think Obamacare is the bane of American existence right now…

No, this does not mean that Obamacare is a net-positive for Democrats at the ballot box. Another 19 percent of wrong-track voters cite Obama (the man) as the reason for their gloom, and Obamacare likely plays into that number (among other things).

But it’s also clear that the issue that was looking like a silver bullet for Republicans six months ago has largely faded as a priority. And this isn’t the first poll to suggest this. A month ago, a new Kaiser Family Foundation survey showed Obamacare more unpopular than ever, but as far as an issue that people actually wanted to see addressed, it ranked behind basically every other major issue.

This gets right to the core of why it looks as if the politics of Obamacare are shifting. Some misinterpret the suggestion of shifting health care politics as equivalent to claiming the law’s approval is rising or that it is becoming a winner for Dems. But that isn’t the argument. Straight approval/disapproval on the law has essentially remained unchanged for years — with some fluctuations around the botched rollout — and it remains a net negative for Dems that must be treated gingerly in red states. Those of us who argue the politics of the law are changing don’t mean to suggest otherwise.

Rather, the point is that the fading of negative headlines — combined with mounting enrollment — are shifting the ways candidates in both parties are talking about the law, potentially allowing Dems to mitigate the damage they might otherwise have sustained from it and to fight it out on other issues.

There’s new evidence that this may be what’s happening.

It’s now clear that the cooling passions over the issue are allowing Democrats more leeway to engage in debates over what is actually in the law, if not in debates over whether that thing called “Obamacare” is good or bad. Via Steve Benen, here is vulnerable Dem Senator Mark Pryor’s new ad, in which he aggressively pushes back on charges that his vote for Obamacare was a vote to cut Medicare benefits, instead arguing that the Medicare reforms he supported are provider side cuts that are good for the program:

It’s true this ad doesn’t mention “Obamacare” explicitly, just as Pryor’s previous ad touting his vote to ban discrimination against preexisting conditions didn’t. But this is exactly the point. Mark Pryor is not campaigning on “Obamacare” in deep red Arkansas. But he now feels safer to engage a debate over its individual provisions, as a way to explain and mitigate the damage from his vote, than he would have a few months ago — precisely because the anger over it has faded.

Meanwhile, to underscore the point, Karl Rove’s Crossroads GPS is running an ad in Arkansas that is very much about the old “Obamacare” that Republicans invented years ago (the one that supposedly cut your Medicare benefits) and the “Obamacare” that Republicans invented last fall (the one that supposedly hurt far more people than it helped). The point is not that this is now a winner for Pryor. It isn’t. Rather, the point is that the politics have changed enough to allow Dems to challenge GOP depictions of it more directly, even as Republicans are still required to campaign against the same fantasy Obamacare that once was certain to deliver them the Senate, before the facts on the grounds changed.

Indeed, thanks to those changing facts, Republicans now must avoid debating the law’s specifics or its future. And they are facing tough questions about those topics now, whereas a few months ago, only Dems were facing tough questions about the law. Pryor’s opponent, Rep. Tom Cotton, continues to refuse to say whether he’d repeal the benefits from the state’s version of the Medicaid expansion, which is responsible for Arkansas’s steepest-in-the-nation drop in uninsured. And he has ducked questions about that drop, too. In this he joins multiple other GOP Senate candidates who have engaged in similar evasions.

Yesterday’s North Carolina Senate debate captured all of this perfectly. Dem Senator Kay Hagan faced tough questions about the law. But so did GOP challenger Thom Tillis, and he ducked them. When asked about the Medicaid expansion, he actually declined to reiterate his opposition to it after Hagan attacked him for opposing it for North Carolina. Instead, he attacked the fictional GOP version of Obamacare — claiming it cuts Medicare benefits — just as Karl Rove’s ad does.

These changing politics may not be enough to save Dems — Republicans may of course still win the Senate. But continuing GOP evasions on the issue suggest that Republicans haven’t won the ideological argument over the law’s goals or — with the exception of the individual mandate — over the key policy mechanisms it employs to accomplish them. Whoever controls the Senate next year, that matters, too.

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