“All-out war” is how NBC News summarized the attitude at the Democratic National Committee toward Joe Biden’s opponent in a story published Thursday.

But in this case that opponent isn’t Donald Trump.

The opponent—or opponents, rather—are the third-party candidates in the race who are threatening to play spoiler this fall by steering disgruntled left-wing voters away from supporting the president. Democrats have had some experience with that over the past 25 years, you might have heard, so they’re setting up a war room in-house to start tearing down those spoilers early.

With good reason. Currently Trump is leading Biden by 2.1 points head-to-head nationally, but in five-way polling that includes the three most prominent third-party candidates his lead expands to 2.7 points. In three-way polling that includes Trump, Biden, and only the most well-known independent, Robert F. Kennedy Jr., Trump’s lead reaches 4.3 points.

Democrats have a Kennedy problem, as has sporadically been the case for most of the past 60-plus years. What can they do to solve this latest iteration?

After the NBC News item dropped, Matt Yglesias considered the nuclear option.

The Democratic Party has had some success lately at promoting weak candidates from other parties for strategic advantage, as you also might have heard. In fact, they’re doing it again right now in Ohio.

Two years ago, Democratic outfits spent money in GOP primaries on ads designed to help crank populist candidates prevail over more formidable mainstream opponents. “Cynical” doesn’t begin to describe the mindset of liberals who routinely warn voters that MAGA Republicans are a threat to democracy and then quietly spend millions of dollars to help those same Republicans advance to the general election.

But that’s what Democrats did in 2022, believing that their own candidates would have an easier time defeating cranks in November. Annnnnnd … they were right.

Little wonder that they’re repeating the strategy in the current Ohio Senate Republican Party primary by promoting Trump-backed Bernie Moreno, who may or may not have a major scandal brewing, over his more moderate challenger, Matt Dolan. If that pays off with a Moreno victory, the party will inevitably contemplate extending their very successful strategy to the presidential race—with a twist.

Instead of steering Trump-loving populist voters toward a Republican crank in a primary, Democrats would attempt to steer them toward an independent crank running against Trump himself.

For both ethical and tactical reasons, the Yglesias nuclear option is very risky.

The logic of Democrats promoting Kennedy in the general election is straightforward. He’s the most prominent vaccine skeptic in America; the grassroots right has become a stronghold of COVID vaccine skepticism; and Trump is deeply compromised on the issue because of the spectacular success of his effort as president to bring the COVID vaccines to market much sooner than expected.

Put it all together and Kennedy stands a real chance of taking more votes from Trump than from Biden on Election Day. All Democrats need to do is publicize his anti-vax credentials.

RFK’s threat to Trump has been clear for a while. Here was Ron DeSantis ruminating about it last October, euphemizing the vaccine issue by highlighting MAGA Republicans’ “anti-Fauci” views.

From the start, pandering to anti-vaxxers was part of DeSantis’ strategy to try to out-populist Trump in the primary. He was attuned enough to Kennedy’s growing popularity on the right that he once promised, if elected president, to “sic [RFK] on the FDA” via some sort of oversight appointment. To prove that he meant business, he even named a vaccine skeptic to be surgeon general of Florida, which has worked out exactly as well as you’d expect.

Trump also understands that he’s on the wrong side of his base on vaccination. He’s been booed at his own rallies for encouraging it; when asked in an interview last year why he doesn’t talk more about Operation Warp Speed, he replied, “I really don’t want to talk about it because, as a Republican, it’s not a great thing to talk about, because for some reason it’s just not.” Still, his vanity sometimes (well, usually) gets the best of him. When Biden celebrated the COVID vaccines during last week’s State of the Union address, for instance, Trump couldn’t resist taking credit in a post on Truth Social.

That also worked out exactly as well as you’d expect among populist commentators. So you can appreciate Yglesias’ thinking: If vaccination is a wedge issue between Trump and the right, shouldn’t Democrats exploit it by quietly promoting a candidate like Kennedy?

I don’t think so. It wouldn’t be ethical. Although, if they’re intent on doing it, there are more and less unethical ways to go about it.

The least ethical approach would be to craft ads aimed at populist Republicans that valorize Kennedy’s vaccine skepticism. “Unlike Trump, RFK stood up to the scientific deep state!” would be unforgivably irresponsible.

It’s one thing to promote bad candidates like Bernie Moreno, knowing that even the “good” Republicans like Matt Dolan who make it to Congress these days are all but destined to turn bad. It’s another to promote beliefs that will induce self-destructive behavior by American citizens, like eschewing vaccination. Vaccine skepticism has cost red states enough innocent lives already.

The more ethical way to promote Kennedy to MAGA voters is to do so indirectly, by commending Trump for good behavior that Democrats know will alienate populists. Imagine a pair of ads, one lavishly thanking him for his work on Operation Warp Speed and touting the number of Americans who’ve had their COVID shots, the other condemning Kennedy for undermining public confidence in vaccines. Those ads would each demonstrate the morally correct position, but the point would be to raise awareness among vax-hating Republicans of the two candidates’ respective positions, benefiting RFK and hurting Trump.

Even so, I don’t like the idea.

For one thing, the more pressure Trump feels from RFK to appease anti-vaxxers, the more inclined he’ll be to keep pace by taking irresponsible positions himself. He’s already started, in fact:

Scientists who watched that clip were mortified. Since 2019, Republican support for mandates requiring schoolchildren to be vaccinated for measles has fallen from 79 percent to 57 percent. That number will not improve if the most influential cultural figure on the American right ends up being browbeaten by Democratic ads into becoming a vaccine skeptic for electoral reasons.

The other reason I don’t like the idea is there’s a fair chance it’ll backfire and end up getting Trump reelected, which would be, shall we say, suboptimal from an ethical standpoint.

Democratic ads celebrating Trump for Operation Warp Speed and/or attacking Kennedy for undermining public confidence in vaccines might cost Trump votes on balance by alienating populist Republicans. But remember that Biden’s message this fall, broadly speaking, will be that his opponent is a full-spectrum freak and anti-democratic wackaloon whose return to power will banish normalcy from American politics forever.

How does one square that message with an ad campaign reminding voters that, when President Trump was faced with a historic crisis in 2020, he did the responsible thing by going all-in on accelerated vaccine development? In a very abnormal cultural moment, he behaved not just normally but wisely.

So, sure, contrasting Trump with Kennedy on vaccines will probably move some crank populists from the former’s camp to the latter’s. But it might move many more anxious swing voters from undecided to pro-Trump by reassuring them that a second Trump presidency won’t be as risky as they assume.

That brings us to the tactical virtues of Yglesias’ scheme. How confident are we that Democrats boosting Kennedy would end up hurting Trump more than Biden? In my case: Not very.

I’ve written about that before, but I understand the argument to the contrary. Jonathan Last made it as well as it could be made in a piece Thursday at The Bulwark.

Yes, he conceded, right now Kennedy is taking more votes from Biden than from Trump in a three-way race. But that’s probably a mirage: Many Democratic voters who prefer him to the president may know nothing about him apart from his famous name. A Democratic ad campaign that called attention to RFK’s record on vaccines would presumably sour most of those left-wing voters on him while enticing hardcore right-wing populists.

By the time November arrives, Last suggests, only anti-vax Republicans who would otherwise back Trump will still respect Kennedy enough to consider supporting him. Which means his candidacy will end up costing Trump more votes than it will Biden.

Could be. This fascinating data set suggests he’s onto something.

Anti-vax leftists have been drifting rightward and pro-vax right-wingers have been drifting leftward for years already. That self-sorting could mean there are relatively few self-identified Democrats left who might be receptive to Kennedy’s message. They’ve all gone and joined the GOP, perhaps becoming “soft” Trump supporters over that period given their history of preferring Democratic policies on other matters.

If so, RFK is a serious threat to Trump. He’s a better fit politically for leftists who defected from the Democratic Party over vaccines than a boorish right-wing authoritarian who, when the chips were down, actually did a good job in jumpstarting a national vaccine initiative. They might consider Trump as a lesser evil relative to Biden but not relative to Kennedy.

And as for “burn it all down” right-wing populists who’d normally support Trump unquestioningly as the craziest anti-establishment candidate in the race, it’s possible that the Kennedy ticket will out-crazy everyone this year:

Kennedy-Rodgers will cost Trump the election. That’s the optimistic view.

Now let me give you the pessimistic one.

For starters, voter ignorance about RFK’s vaccine views cuts both ways. It may be true that most voters outside the populist right will turn against him as they’re educated about his beliefs. But it’s anyone’s guess how many anti-vax Democrats have stuck with Biden this long, perhaps very reluctantly, believing that he reflects their beliefs better than Trump does notwithstanding their skepticism about vaccines.

What will those voters do once a Democratic ad campaign highlighting Kennedy’s anti-vaxxism shows them that there’s a candidate on the ballot who matches their politics more closely than the president does? When Nate Silver examined the data set I posted above, he saw potential peril for Biden: “Vaccination is popular overall (more than you’d gather from reading Twitter) but non-vaxxers are often cross-pressured voters, can imagine some drifting out of the D coalition.”

The president’s left-wing coalition is also famously less enthusiastic about him than the Republican coalition is about Trump, leaving one to wonder how “soft” pro-vaccine Biden voters might respond to a Democratic ad campaign that raises Kennedy’s name ID considerably—even in the course of highlighting his vaccine skepticism. Many progressive voters might support vaccination without feeling passionate about it while feeling very passionately that Biden hasn’t done enough to solve inflation, climate change, Israel’s operations in Gaza, etc. Others might disdain the American political establishment writ large so intently that they’re open to casting a protest vote for a radical if one should end up gaining any traction in the polls.

Kennedy could fit the bill for these cohorts, despite his anti-vax kookery for the group that doesn’t care much about vaccines and because of it for the group seeking to send a statement. The better known he becomes, the more attention those cohorts will pay him. A Democratic ad campaign on his behalf would help.

The other problem with thinking that anti-vax populist Republicans are more likely to be wooed by Kennedy than Democrats are is that … that’s just not how right-wing politics works in the Trump era. Sure, in theory, a MAGA voter might be so irate at Trump for spearheading the COVID vaccines four years ago that he or she would switch to RFK and resolve to be immovable.

But in practice, the idea is laughable. A movement committed to finding excuses for its leader even if he shoots someone on Fifth Avenue isn’t going to decide that Operation Warp Speed is the one red line they’ll never forgive him for crossing. Their excuse will be, as it always is, that Trump simply received “bad advice” from his treacherous establishmentarian aides as president and that he’ll do better on vaccines in a second term when he’s surrounded by a phalanx of cranks.

They’ve stuck with him through four indictments. They’re not changing now.

DeSantis’ ill-fated campaign proves it. He did everything he could within reason to get to Trump’s right on vaccination yet made it through exactly one primary before dropping out. If Trump’s “weak” record on vaccination couldn’t convince populist anti-vaxxers to support their second-most favorite Republican for the party’s nomination, it’s not going to convince them to throw their votes away on Kennedy with the, ahem, “existential threat” of a second Biden presidency looming in November. 

And that includes those formerly Democratic anti-vaxxers I mentioned earlier who have been trending right since 2020. Amy Walter noted a fascinating contrast between the two nominees in a piece for the Cook Political Report on Thursday: Many who voted for Trump as the lesser of two evils in 2016 eventually became enthusiastic supporters over time, but those who chose Biden for the same reason in 2020 have not.

By this point in his presidency, Trump had converted anti-Clinton voters into pro-Trump voters. By the summer of 2020, according to NBC polling, 75% of Trump voters said they were voting for him, while 20% said their vote was really a vote against Biden. This is what gives Trump such a high floor of support. However, this pro-Trump constituency wasn’t big enough to defeat Biden.

Unlike Trump, Biden hasn’t converted those who disliked Trump into pro-Biden voters. Since 2020, the share of those who say their vote is more for Biden than it is against Trump has remained between 31% and 36%. Meanwhile, those who say their vote for Biden is really more of a vote against Trump has stayed consistently between 58% and 62%.

I’d bet that most left-wing vaccine skeptics who turned to the GOP over the past four years have already become true-believing MAGAs over that period. You know what they say about converts and zealotry: A voter who’s willing to do something as wrenching as abandoning their old political party for a new one, knowing that that new one operates as a cult of personality, isn’t going to be a stickler about maintaining a degree of intellectual independence.

They’re probably Trump cultists now. Even if Democratic ad-makers offer them Kennedy as a more simpatico alternative ideologically, the “Fifth Avenue” duty that comes with being a Republican in 2024 will keep them in the fold behind Trump.

One more point. As with all questions related to the pandemic, the debate over vaccines is less salient now on both sides than it was four years ago.

Just 28 percent of Democrats and 12 percent of Republicans still call COVID a “major threat” to the population’s health. As of early February, less than half in both parties cared enough about COVID vaccinations to be fully up to date on their shots. Practically everyone in the U.S. has acquired a degree of immunity from the virus by this point, ending the era of frightening waves of serious infection that caused runs on hospitals. No one talks seriously about COVID vaccine mandates anymore.

In the thick of the pandemic, when vaccines became the main front in the culture war, an RFK candidacy would have been an interesting play to try to peel off disgruntled populist Republicans. But the right has moved on: Anti-vaxxism persists, but the great cause in 2024 is retribution against the “deep state,” not resisting the jab. There’s only one candidate for that task. And it ain’t Robert F. Kennedy Jr.