Two elected officials have weighed in over the past several days on the effort to vaccinate as many Americans as possible.

The first was President Biden. During a July 4 speech at the White House, he again encouraged the country to be vaccinated against the coronavirus, referring to covid-19, the disease it causes.

“Covid-19 has not been vanquished,” he said. “We all know powerful variants have emerged, like the delta variant, but the best defense against these variants is to get vaccinated. My fellow Americans, it’s the most patriotic thing you can do. So, please, if you haven’t gotten vaccinated, do it — do it now for yourself, for your loved ones, for your community and for your country.”

The second official to offer thoughts was Rep. Marjorie Taylor Greene (R-Ga.), who weighed in on Twitter.

“No one cares about the Delta Variant or any other variant,” she wrote. “They are over covid & there is no amount of fear based screaming from the media that will ever force Americans to shut down again.”

According to analysis from Harvard University’s Geographic Insights team, Greene’s district is one of the least densely vaccinated in the country. It seems safe to say that Greene is among those who’ve rejected a dose of the vaccine.

But that the vast majority of the least-vaccinated districts are represented by Republicans, often far-right Republicans like Greene, is not a surprise. There’s a strong correlation between politics and vaccination rates — stronger than any other metric.

A Washington Post-ABC News poll released over the weekend shows a stark divide in vaccination hesitancy by political group. Overall, about a fifth of Americans say they definitely won’t get vaccinated. That’s about the percentage for independents and Whites overall. But among Republicans and White conservatives, the figure is more than a third.

If you’re skeptical of those results, fair enough. But there is a correlation in the real world: States that voted for Donald Trump in 2020 have almost uniformly seen lower densities of vaccinations than states that voted for Biden. About the time that the Johnson & Johnson vaccine was paused, the two groups of states diverged, with blue states continuing to add vaccinations far faster than red ones.

Among the Biden-voting states that are below the best-performing red state — Florida — are four states that only became blue in November. They voted for Trump in 2016. Only one state that voted against Trump in both 2016 and 2020 is below the red states: Nevada.

What’s more, there’s actually a correlation between how robustly a state voted for Trump or Biden and the rate of vaccinations. Setting aside D.C., an outlier both in the vote margin and in the rate of vaccinations, plotting vaccination rates against 2020 votes creates a remarkably straight line of points.

In statistics, correlation between two sets of data is measured using a value called r. A perfect correlation yields an r-value of 1. The correlation between 2020 vote and vaccination rates is 0.8. Take out D.C. and it jumps to 0.87. (The dashed line on each graph gives some sense of how strong the correlation is. Stronger correlations will generally mean more dots clustered around the line.)

There are other attributes of each state that correlate to vaccination rates, though none as strongly. Education, for example, has an r-value of 0.67: the more college graduates there are in a state, the more likely it is to have a high vaccination rate. But when we plot that figure against vaccination rates, you see that this also correlates to the 2020 vote, since states with more college graduates also tended to vote more heavily Democratic.

Income correlates to education, since people with college degrees tend to earn more money. So, again, we see a good correlation between median income in a state and vaccination rates, with an r-value of 0.68. But, again, this also correlates to the 2020 vote.

One characteristic that doesn’t correlate strongly to vaccination rates is the racial density of states. The percentage of a state’s population that is White is not correlated to vaccination rates, with some heavily White states (like Vermont) having high rates. At the outset of the vaccine rollout there was concern that non-White Americans would be more hesitant to get the vaccine, but there’s also no real correlation between the density of the Black population in a state and vaccination rates.

All of this reinforces the idea introduced by that poll: Republicans and conservatives are more likely to say they won’t get vaccinated. For those who’ve observed American politics in the past 18 months, it’s not a mystery why. Treating the coronavirus pandemic as a dire threat has become entangled with Democratic policy priorities, no doubt thanks in part to Trump’s effort to dismiss the pandemic as minor as he sought reelection.

We also see from the Post-ABC poll that people who see their own risk of contracting the virus as low are more likely to say they won’t get vaccinated. A fifth of those who see their risk as low say they definitely won’t get a shot, compared with about 1 in 8 of those who see a more elevated risk.

It’s not all politics, certainly. There are a lot of reasons people might opt not to get a vaccination, despite the obvious and increasing evidence of its efficacy, even when combating a more virulent iteration of the virus such as the delta variant. But the data suggests strongly that some part of it is politics — which suggests that maybe this level of hesitancy might have been avoidable.