The other day, the Dem-aligned Senate Majority PAC made a splash by going up in Kentucky with a very harsh ad hitting Mitch McConnell over his previous support for Social Security privatization. The ad linked that stance to an assertion that McConnell had “rearranged his portfolio” after private calls with a top Treasury Department official, implicitly suggesting McConnell had milked inside connections to bolster his own retirement security while gambling with that of others.

The ad ticked off the McConnell campaign, which circulated a fact check that said it had oversimplified the claims in the original article on which it was based and overlooked the fact that it had alleged no wrongdoing.

The McConnell campaign is trying to get TV stations to stop running the ad. I’ve checked in with Kentucky stations, and most declined to reveal their plans for the spot, though an official at one — Fox affiliate WDRB — told me: “We reinstated the spot, finding the assertions factual.”

A spokesman for Senate Majority PAC told me the ad is still airing “on every station we bought on.”

The dust-up shows that Democrats are pushing hard to make Social Security privatization a sleeper issue in the last days of the Kentucky Senate race. And they were handed an unexpected opening in this regard, when McConnell himself made an offhand reference to his own involvement with George W. Bush’s Social Security privatization efforts in 2005. “He wanted us to try to fix Social Security,” McConnell said during a recent speech. “I spent a year trying to get any Democrat in the Senate…to help us.”

As Steve Benen notes, bringing this up was a surprising move, given how deeply unpopular the privatization push was at the time. Democrats have since been hammering the issue, and McConnell has been asked by reporters to clarify his plans for Social Security. When reporter Joe Sonka asked whether a GOP Senate majority would pursue privatization, McConnell replied: “I’m not announcing what the agenda would be in advance,” though his spokesman clarified that he wasn’t interested “in reviving the 2005 debate.” Meanwhile, according to one local report, McConnell today “evaded questions” on the topic.

The Grimes campaign, by contrast, is pushing the topic hard. When McConnell brought Bobby Jindal to Kentucky to campaign for him the other day, the Grimes camp quickly pointed out that Jindal had supported the 2005 privatization push, too. And on the stump, Grimes has repeatedly floated variations of the idea that unlike McConnell, she would never gamble away her grandmother’s Social Security on the stock market.

The larger story here is that Democrats are going back to an old standby, not just in Kentucky, but in multiple other races, too, such as Alaska, where Senator Mark Begich has talked about expanding social insurance for the elderly, and in Iowa, where Democrats are running ads lacerating Joni Ernst on the topic. And there really is a legitimate policy contrast of sorts here. Ernst really has talked about privatizing Social Security “as an option,” and her Democratic opponent, Bruce Braley, really does oppose it under any circumstances. And McConnell really did remind everyone of his own very real role in Bush’s privatization drive. As Michael Tomasky puts it:

It will be a theme of Grimes’s closing week in a race that the experts might have written off a little prematurely…they’re doing it because it often enough does work. Old people vote in midterms, so it stands a much better chance of having an impact than a last-second student-loan scare. And it’s not a stretch of the facts. McConnell did what he did in 2005, and he was foolish enough to boast about it in public less than two weeks before an election.