July 4 has come and gone, and the Biden administration missed its goal of vaccinating 70 percent of Americans by then. As plenty have noted, this owes to something that is largely outside the administration’s control: Republican vaccine skepticism. A new Washington Post-ABC News poll this weekend showed 93 percent of Democrats say they’ve either received a vaccine or plan to, while just 49 percent of Republicans say the same. That has played out in the real world, too, as Philip Bump notes, with a strong correlation between how red a state votes and how unvaccinated it is.

So, what to do about it? Health officials warn that, even though the virus has been significantly undercut by existing vaccinations, emerging variants like the delta variant pose a big problem, in that the vaccines we have are likely less effective against them (at least to some degree). And less vaccination means variants — possibly even more deadly and vaccine-resistant ones — can emerge more easily.

The short answer to that question is: It might be time to get creative, because what’s been done hasn’t really worked. And the force of the vaccination effort is about to run into the immovable object that is GOP vaccine skepticism.

Polling has shown Republican vaccine skepticism to be remarkably stubborn.

The Kaiser Family Foundation has polled vaccine views every month since late last year. And in every poll, between 28 percent and 38 percent of Republicans said they would either definitely not get vaccinated or would do so only if required to. Its most recent poll shows 23 percent would definitely not get vaccinated, which is basically right around where it’s been since December (25 percent), with an increase a few months ago and a dip in April.

Similarly, YouGov polling has shown perhaps a slight decline in Republicans who say they won’t get vaccinated, but the data has jumped around too much to glean a whole lot.

One poll recently did show a significant drop, but there are reasons to be skeptical of the finding. The Monmouth University poll showed 26 percent of Republicans saying they probably would never get vaccinated — down from 43 percent in April and 36 percent in March. But somehow the data also showed Republicans being less reluctant to get vaccinated than independents, which is not something we’ve seen in any other poll.

The Biden administration does have something of an idea. 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.

There is reason to be skeptical of this plan. One is that, over the past several months, vaccine skepticism has become so ingrained that convincing these people will seemingly be difficult because of that. Another is that the decline of the virus in American life has created less urgency.

There’s also the possibility that the most vociferous vaccine opponents will react angrily. Rep. Marjorie Taylor Greene (R-Ga.) on Tuesday likened the door-to-door effort to Nazi “brownshirts” (even though nobody would, you know, actually be compelled to receive a vaccine). She’s among the most extreme members of Congress, but she’s hardly the only one rallying people against the government’s vaccination program, and a more personal government-led effort carries the potential for a backlash and even ugly scenes.

There is some reason to believe this might move a small number of people. The Kaiser polling, for instance, shows 12 percent of Republicans aren’t set against the vaccine but say they will “wait and see.” Perhaps local community members will help them “see.”

But one of the undersold reasons for GOP vaccine skepticism is not the safety of vaccines, but their necessity. And on this count, the Post-ABC poll also provides some insights. It asked whether people believed the threat posed by the delta variant is being exaggerated by health officials who say it’s more dangerous. Overall, 35 percent of U.S. adults said it was, but that number spikes to 81 percent among those who say they definitely won’t get vaccinated. And it goes up to 84 percent among Republican-leaning Americans who definitely won’t get vaccinated. (Just 3 percent of them believe officials are accurately describing the danger of the delta variant.)

And this is a group of people that was already far less concerned than others about the initial strains of the virus. Are they suddenly going to get vaccinated when restrictions have been relaxed if they don’t see as much danger in the delta variant? Or are they going to, like Sen. Rand Paul (R-Ky.), wait to see if the situation gets worse before they decide to get vaccinated?

In the end, what is clearly missing from this effort is a more forceful GOP push. Some Republican doctors in Congress (not including Paul) recorded a video in April urging vaccinations. Some Republican former governors like Wisconsin’s Scott Walker and New Jersey’s Chris Christie have appeared in ads. But other than that and a few comments from the likes of polio-surviving Senate Minority Leader Mitch McConnell (R-Ky.), it’s been very quiet.

Former president Donald Trump, despite very much wanting credit for the production of the vaccine, spent months declining to tell people to actually get it. He also didn’t disclose that he received it in January, meaning we didn’t find out until March. Since then, he’s offered a few comments urging vaccinations, but a YouGov poll recently showed only 36 percent of people who say they won’t get vaccinated believe Trump has been vaccinated — compared with 54 percent overall. And fewer than half of people who are resisting vaccination think Trump actually supports it.

It’s possible a door-to-door campaign might be somewhat effective in combating vaccine skepticism, but what if someone instead simply dumped millions of dollars into an ad playing up the fact that Trump was vaccinated and playing video of his handful of comments advocating for it? It would sure be helpful if Trump actually participated in such an ad — as every other living former president has — but that wouldn’t even be strictly necessary. Some of these comments even carry the important visual imprimatur of Trump having said them on Fox News. The ad practically writes itself. But right now such important GOP endorsements are being drowned out by the likes of Tucker Carlson’s show using innuendo and poor research to cast doubt on the vaccines.

Yet even that might not work as well as some might imagine. The same YouGov poll showed 71 percent of Republicans overall believe Trump supports vaccination, and yet only about half say they have gotten one or will get one. In other words, it’s an extraordinarily complex problem with no simple solutions. The ones that have been tried haven’t moved the needle much, so the Biden administration is trying something new — now that we’ve come to the moment in which we’re running out of non-skeptics to vaccinate.