The latest message for swing-district Republicans is reminiscent of a Tea Party-era rallying cry: "Get your government hands off my Medicare."

The latest campaign ad from Rep. Dave Brat (R-Va.) accuses challenger Abigail Spanberger of favoring a "health care plan that would bankrupt Medicare as we know it." A spot from Rep. Andy Barr (R-Ky.) says challenger Amy McGrath wants to "end Medicare as we know it." An ad from Rep. Bruce Poliquin (R-Maine) warns that his challenger, Jared Golden, "will end Medicare as we know it" — sounds familiar — and will "alter Medicare while its future is in doubt."

Each ad is talking about "Medicare for All," the idea of turning an insurance program designed for the elderly into universal health insurance that's most regularly associated with a bill from Sen. Bernie Sanders (I-Vt). It's costly, in the trillions of dollars, in part because it would not curtail existing Medicare benefits. But in the president's words, Democrats want to "cut Medicare to pay for socialism." It's a zero-sum game, Republicans say, and Democrats want Medicare recipients to lose their benefits.

Democrats have been bracing for this attack and are taking a decidedly Br'er Rabbit approach. Republicans want this election to be about health care? Fine, say Democrats: Jump in to this briar patch, where every candidate is armed with evidence of how Republicans are undermining Medicare through tax cuts. Before and after Labor Day, Democrats have piled onto the air with Medicare ads and ads about shielding the most popular part of the Affordable Care Act, its protections for people with preexisting conditions.

"If this is an election about Medicare, it's an election that Republicans are losing," said Tyler Law, the Democratic Congressional Campaign Committee's spokesman.

Republicans have, however, won elections on Medicare. In 2010, and in every election thereafter, the most potent Republican attack line on health care was that Democrats had put Medicare at risk by passing the ACA. That bill projected $800 billion of savings from Medicare over 10 years, which Republicans transformed into $800 billion of Medicare cuts.

So this attack is audacious but not new. The problem, say Democrats, is that Republicans can't credibly promise that they'll protect Medicare. During the 2016 campaign, Donald Trump's pledge not to touch Medicare or Social Security was an underrated source of his crossover appeal. But every other day, a leading House Republican or a member of the Trump administration says that "entitlement reform" is on the agenda if the party holds Congress — "probably next year," said Larry Kudlow on Monday morning. Democrats, meanwhile, are attempting to capitalize on  voters' view of them as the health-care party, arguing that they can find plenty of money to expand Medicare without hurting anyone who depends on it.

"This is the zero-sum framework that's always evoked — that in order for us to get something good, someone else has to suffer," said Alexandria Ocasio-Cortez, who has campaigned for candidates who favor Medicare for All since her upset win in the New York Democratic primary over Rep. Joe Crowley. "We have to refute that logic, because the jig is pretty much up. Working Americans know now, more than ever, that the economy is not built for them."

Here's the twist. Remember how two of these three attack ads accused Spanberger and  McGrath of favoring Medicare for All? Neither has actually endorsed it; Spanberger has said she doesn't support the Sanders bill, and so has McGrath. A quote from McGrath in the attack ad is chopped out of a longer answer, in which she said that "single payer would be the way to go" if the current health-care system didn't exist. 

Of the three candidates, only Golden has come out for Medicare for All. Spanberger and McGrath have endorsed more incremental changes to the country's health-care system.  But every Democrat is being painted with the same brush.