The true extent of coronavirus vaccine misinformation is something that, like all misinformation, is difficult to gauge. Many Americans — particularly Republicans — are declining vaccination, but plenty of them are doing so because of a perceived lack of necessity. From there, various theories abound, including about what’s in the vaccines and potential side effects.

But when it comes to epitomizing how much such misinformation has penetrated our society, it’s difficult to do better than this: a federal judge inserting a baseless claim about vaccine deaths in a completely unrelated opinion.

U.S. District Judge Roger T. Benitez’s ruling striking down an assault-weapons ban in California is a momentous one that, as The Washington Post’s Timothy Bella and Rachel Siegel write, could reverberate. Such rulings cue up the possibility that the newly conservative-dominated Supreme Court might eventually decide to take up the case — a possibility that could bear on future gun rights cases.

Benitez’s ruling was hailed by supporters of gun rights not just because of that but because of the detailed case he laid out, which echoes many of their most popular arguments about the banning of guns such as AR-15s. Benitez labeled the ban a “failed experiment.” He provocatively suggested such guns were necessary for militias, citing his birth country of Cuba and the revolution there. He likened the guns to Swiss army knives and compared the numbers of deaths caused by rifles and knives.

But Benitez perhaps inadvertently undermined his arguments by reaching for another comparison — one between deaths from mass shootings and coronavirus vaccines.

Not the coronavirus itself, mind you, but specifically coronavirus vaccines.

“The evidence described so far proves that the ‘harm’ of an assault rifle being used in a mass shooting is an infinitesimally rare event,” Benitez wrote. “More people have died from the Covid-19 vaccine than mass shootings in California.”

This is, to put it diplomatically, completely baseless. Such claims often come with citations to back them up, but Benitez offers none, probably because there isn’t one.

The state of California has in the past month released data on what are known as “breakthrough” coronavirus infections in those who received vaccinations. As of May 19, there were 4,771 breakthrough cases, with 37 people dying. But these aren’t people who died of the vaccine; they’re people who died after contracting the coronavirus, despite receiving the vaccine. Such cases are, to borrow Benitez’s phrasing, infinitesimally rare given California has vaccinated more than 20 million people.

But what about people who died after receiving the vaccine without contracting the virus? Again, there’s nothing to back up the judge’s claim. The early days of the vaccination campaign were marked by occasional media reports of the recently vaccinated dying. But those deaths weren’t actually linked to the vaccine. And given the scale of the vaccination campaign and how it was initially geared toward older people, it was always likely plenty of people would die of something in the days or weeks after vaccination.

The Centers for Disease Control and Prevention recently said that, as of May 24, “a review of available clinical information, including death certificates, autopsy, and medical records has not established a causal link to COVID-19 vaccines.” The CDC has linked one specific vaccine, from Johnson & Johnson, to potential blood clotting in a very small number of cases. This led it to temporarily halt the vaccine’s use. But as of last month, there were just 28 cases of clotting and three deaths that were being investigated.

Those are nationwide numbers. Even if the link were conclusive and this were just in California — too very big ifs, it bears noting — that still wouldn’t be more than California’s mass shooting deaths. Mass-shooting deaths are a somewhat subjective metric, but 12 people total were killed in two mass shootings alone, in San Jose last month and Orange County in March.

So where is Benitez getting his data? It’s not clear, and his office didn’t respond to a request for comment Monday morning.

A likely culprit would seem to be the misinformation floating around about self-reported potential side effects of the vaccines. The likes of Fox News’s Tucker Carlson have cited the data from the U.S. government’s Vaccine Adverse Event Reporting System (VAERS) to raise questions about a potential link between the vaccines and deaths. As I wrote last month, though, the data in those reports is unverified, and the links to potential side effects including deaths are unproved. It’s effectively the government asking people to report things that can then be investigated.

But while Carlson’s effort to spotlight the data was pitched, as it often is on his show, as him just asking questions (albeit extremely suggestive ones that often involve faulty comparisons), Benitez went even further than that. He effectively stated that there was some kind of known universe of vaccine-caused deaths and that it was greater in California than mass-shooting deaths. There is just nothing to back it up.

The fact that this found its way into his supposedly (according to gun rights activists) well-reasoned and potentially consequential judicial opinion raises plenty of questions about the rest of it — not to mention our society.