Thanks to Fox News, the Republican Party is embroiled in a furious debate over whether it was a good idea to save millions of American lives. 

Florida Gov. Ron DeSantis’ nascent campaign for the Republican presidential nomination is floundering in the early going. He entered the race last month with a sizable polling deficit behind former President Donald Trump, his Twitter Spaces announcement event was a disaster, and his initial rollout hasn’t produced a bump in his support. DeSantis has seemed reluctant to go after his chief opponent, and when he has the results have been lackluster. 

But on Thursday afternoon, his campaign opened a new line of attack, targeting the former president for his role in the development of the COVID-19 vaccines. The “DeSantis War Room” posted a video on Twitter of an Iowa town hall attendee telling Trump “we have lost people because you supported the jab.” The DeSantis account reported that Trump responded “by praising the COVID mRNA shots, doesn't acknowledge any of the adverse effects.”

The DeSantis camp’s anti-vax attack on Trump speaks to the influence of right-wing media outlets like Fox in shaping the battlefield for the 2024 primary campaign. Their reflexive support for Trump over the years on issues like his role in the January 6 insurrection, his noxious racism, and his various alleged crimes put those topics off-limits for his opponents. But while some at Fox initially credited Trump with ensuring the development of the vaccines, the network paved the way for the DeSantis campaign’s salvo by spending much of the last two-plus years stoking fears among its viewers about the shots.

Fox emerged as the most ferocious opponent of the COVID-19 vaccines, which provide crucial protection with a minimal risk profile and have prevented millions of American deaths from the virus since their initial U.S. deployment in December 2020. The network’s most popular figures regularly denounced the shots as dangerous and ineffective and the vaccination campaign as a nefarious plot to control Americans. Fox’s coverage worsened over time, and by the early weeks of 2023 a whopping 78% of the network’s vaccine segments included claims undermining vaccinations. The results have been devastating, with Republicans getting vaccinated against COVID-19 at lower rates than other Americans and dying from it at higher ones.

Fox’s lethal coverage of COVID-19 vaccines presented an opportunity for ambitious politicians like DeSantis, who is particularly attuned to what happens on the network and in the broader right-wing press. DeSantis once touted his own efforts to distribute the vaccines, which he credited with “saving lives.” But as the right’s discourse changed, he changed with it.

DeSantis cozied up to the GOP’s anti-vax wing — and used his power as governor on their behalf. DeSantis’ Florida is the only state that does not recommend the COVID-19 vaccine for children, and it “recommends against males aged 18 to 39 receiving mRNA COVID-19 vaccines” after a flawed study that was politically tainted by the vaccine skeptic DeSantis appointed as the state’s top medical officer found the shots were harmful for that group. DeSantis even called for a grand jury to investigate “any and all wrongdoing” related to the vaccines and “bring legal accountability to those who committed misconduct.” 

Now DeSantis’ campaign is deploying the vaccines as a wedge issue, trying to make the case that the GOP electorate should oppose Trump due to his involvement in their development. The conservative reaction has been diverse, with Never Trumpers criticizing DeSantis for promoting “anti-vax nonsense,” anti-anti-Trumpers making excuses, and right-wing anti-vaxxers denouncing Trump.

One person who hasn’t weighed in is Rupert Murdoch, the Fox head and reported DeSantis supporter who was among the first to get the shot — then abandoned his viewers to the virus.