As the U.S. grapples with an uptick in COVID-19 cases driven by the highly contagious Delta variant, a new Washington Post-ABC News poll shows a stark partisan divide in vaccinations: 86% of Democrats have received at least one COVID-19 vaccine shot, compared to just 45% of Republicans.

The top 21 states (including D.C.) with the highest adult vaccination rates all went to Joe Biden in the 2020 presidential election. On the other hand, 16 of the 17 states with the lowest adult vaccination rates broke for Trump.

Utah’s Republican Governor Spencer Cox has bemoaned the fact that politics has muddied the medical waters. Appearing on CBS’ Face the Nation this past weekend, he said, “that politics is becoming religion in our country, that politics is becoming sport and entertainment in our country, that everything is political. It’s a huge mistake. And it’s caused us to make bad decisions during this pandemic and in other phases of our life as well. So it’s deeply troubling.”

Arkansas Gov. Asa Hutchinson, another Republican, also expressed dismay about vaccine hesitancy in the GOP. His state has one of the lowest vaccination rates in the country – 34.57%. On Sunday, appearing on CNN’ State of the Union, he said, “If we stopped right here, and we didn’t get a greater percent of our population vaccinated, then we’re going to have trouble in the next school year and over the winter.”

CNN reports that new cases in Arkansas are five times the nationwide rate.

The Washington Post explains how President Joe Biden wants to tackle the red-blue divide:

Biden said Tuesday that the government would be dispatching people to go door-to-door and visit places of worship, urging people to get vaccinated and offering to make it more convenient to do so. The idea is that local doctors and medical experts might be more convincing to vaccine skeptics.

But even that public health measure has been met with GOP criticism. Rep. Marjorie Taylor Greene, the Republican agitator from Georgia, compared the door-to-door effort to the WW2-era brownshirts in Germany who aided the rise of Nazism.

(White House press secretary Jen Psaki said on CNN Wednesday, “We don’t take any of our health and medical advice from Marjorie Taylor Greene.”)

So what will move the needle of GOP vaccine adoption? Writing in 538, Daniel Cox, a researcher at the conservative American Enterprise Institute has an idea: peer pressure. From Cox’ piece:

Americans whose immediate social circle was entirely vaccinated were far more likely than those with fewer vaccinated friends to have gotten the vaccine themselves per the study by the Survey Center on American Life. And despite reporting higher rates of vaccine hesitancy overall, this was true among Republicans as well. Ninety-three percent of Republicans whose friends were at least partially vaccinated had also been vaccinated. By contrast, only 19 percent of Republicans with just a few or no friends who were partially vaccinated said that they had gotten the jab.