Earlier this week, Sen. Ted Cruz (R-Tex.) joined Sean Hannity on Fox News to discuss the situation at the U.S.-Mexico border and, specifically, what Hannity called “the biggest superspreader in the country.”

“I’m going to argue, you know, the high rate of covid positivity at that border — any American that is infected because Joe’s not enforcing the laws of this country, you can blame Joe Biden for covid,” Hannity said, claiming vaguely that migrants crossing the border are driving the current surge in coronavirus cases. “And if you die, I would put the blame on him, too. Why won’t they stop this superspreader event? Because it’s happening in the hundreds and hundreds of thousands.”

“Sean,” Cruz replied, “you’re exactly right.”

Sean was not exactly right. He was not even partially right. Nor was Cruz right when he started riffing on a Fox News report about 7,000 migrants in the city of McAllen, Tex., being released while coronavirus-positive.

“McAllen is a city, its population is about 140,000,” Cruz said. “That means 5 percent of the population of the city consists now of illegal immigrants who tested positive for covid that Joe Biden and Kamala D. Harris are just dumping there, one after the other after the other because they won’t enforce the law.”

Nope. Wrong.

Before I explain why, it’s worth considering why Hannity and Cruz are making the claim. There’s a long history of scapegoating immigrants as vectors for disease. Even before the coronavirus pandemic, President Donald Trump’s insistent demand for a wall on the border often centered on the untrue claim that migrants posed a “tremendous medical problem,” as he put it in 2018, because of diseases they purportedly carried.

A poll released by Axios this week showed that a third of respondents identified “people from other countries traveling to the U.S.” as being to blame for the current surge in coronavirus cases. It’s a response that obviously includes migrants crossing the border and one that was the most commonly offered target of blame among unvaccinated respondents.

In case Hannity’s unsubtle presentation didn’t make this clear, it’s politically useful for the right to blame the pandemic on migrants (as has happened repeatedly) in part because it shifts blame directly onto President Biden and in part because it specifically shifts blame away from the unvaccinated — a group that is mostly made up of Republicans, according to Kaiser Family Foundation polling.

This idea depends on three key misunderstandings: a misunderstanding of the surge in arrivals at the Mexico border, a misunderstanding of how migrants are released from federal custody and a misunderstanding of where the pandemic is actually at its worst.

Misunderstanding the migration numbers

There’s no question that an unusually large number of migrants are being apprehended at the U.S.-Mexico border. So far this fiscal year (which began last October), Customs and Border Protection data show that more than a million people have been apprehended by the Border Patrol. In June alone, there were more than 178,000.

But there are two ways in which a migrant might be apprehended at the border. The first is an apprehension under Title 8 authority, which is the sort of detention that you would likely generally think of when thinking of an apprehension at the border: an agent encounters someone at the border, for example, and takes them to a detention facility. The other is a Title 42 detention. Implemented last year under Trump, it uses the dangers of the pandemic as a rationale to immediately turn people away at the border. Title 42 expulsions are immediate or near-immediate and, given that they rely on a novel interpretation of the law, controversial.

The result of this two-track process of stopping migrants is that most of those who are counted among the numbers of the apprehended are, in fact, soon expelled from the country. In other words, it’s not the case that some 170,000 people were apprehended crossing into the United States in June, only to be allowed to then move about the interior of the country. More than 100,000 of them were expelled under Title 42.

Nearly all of those who were expelled were individual adults traveling alone. This is important in part, because families and children are more resource-intensive for the government to deal with. But it’s also important because a large number of those expelled under Title 42 simply try to enter the country again.

Government data analyzed by the American Immigration Council indicate that 40 percent of those apprehended at the border this year had been apprehended at least once before during the preceding 12 months. In other words, more than 400,000 of the apprehensions made at the border were of people who were apprehended at another point in the past 12 months. Title 42 expulsions, the American Immigration Council wrote in a recent report, “has created a distorted picture of the total number of people crossing the border.”

To our original point, if 4-in-10 apprehensions were of people who were apprehended at some point in the preceding 12 months and expelled from the country, that means that they weren’t walking around the United States spreading the coronavirus.

The Biden administration has faced enormous pressure from the left to end Title 42 expulsions but, in addition to the resurgence of coronavirus cases, it’s obviously politically useful for Biden to be able to quickly expel tens of thousands of migrants each month. Advocates justifiably suspect that this, not public health, is the administration’s primary motivation for keeping the rule in place.

Even with Title 42 in place, there are more than 75,000 migrants who were apprehended at the border in June who then stay in the United States. The majority of them, however, remain in the custody of federal, state or local officials, according to CBP data. Some are transferred to Immigration and Customs Enforcement. Others are turned over to local law enforcement because of outstanding warrants. The rest are given “humanitarian release,” with notices to appear for hearings within six months.

It’s this group, about 11 percent of those apprehended at the border in this fiscal year, who are the people being blamed for the coronavirus surge. But, again, that’s in part because people don’t necessarily understand what happens after a migrant is released.

Misunderstanding how migrants are released

There are obvious reasons that the federal government would likely not test every person arriving at the border for the coronavirus. The rapid tests that are now widely available still take 15 minutes, and in a process aiming to move tens of thousands of people through as rapidly as possible, 15-minute pauses add up. (To that point, in some cases, formal notices-to-appear have been replaced with a faster form called an I-385.) Nor, of course, are such tests free. But it is not the case that migrants arriving in the United States go untested, nor that there aren’t existing protections against the spread of the virus.

A spokesperson from CBP provided The Post with a blanket statement about the organization’s coronavirus precautions:

“CBP provides migrants with [personal protective equipment] from the moment they are taken into custody, and migrants are required to keep masks on at all times, including when they are transferred or in the process of being released. If anyone exhibits signs of illness in CBP custody, they are referred to local health systems for appropriate testing, diagnosis, and treatment. CBP takes its responsibility to prevent the spread of communicable diseases very seriously. We value our partners in local communities whose work is critical to moving individuals safely out of CBP/USBP custody and through the appropriate immigration pathway.”

There are three important parts to that statement.

The first is the assertion that detained migrants are given and required to wear masks. In practice, this has not always been enforced at Department of Homeland Security facilities. An inspector general’s report focused on an ICE detention center in Mississippi that was released last month found that mask-wearing and social distancing were not enforced earlier this year.

The second is that detainees exhibiting symptoms of illness are tested and, if found to be covid-positive, quarantined. This appears to be the extent of testing by CBP, but, according to an agency spokesperson, every migrant who is transferred to ICE is tested on arrival.

The third important part of that statement is that acknowledgment of the “partners in local communities” that do the work of moving people out of CBP custody. Which, in nearly every case, is how things work. Someone released from CBP custody is then bused to a nongovernmental organization that provides temporary shelter and assistance in arranging transportation to their destination elsewhere in the country, usually in places where their families live. And, in the past year, that process has generally included testing for the coronavirus.

Consider McAllen, Tex. There, the primary agency responsible for facilitating the transition from CBP custody is Catholic Charities of the Rio Grande Valley. According to Brenda Riojas, spokesperson for the Catholic Diocese of Brownsville, the number of migrants released to the group each day varies from a few hundred to more than 1,000. But for each, the process is the same.

The migrants are dropped off by CBP at a testing location in McAllen. Those who test negative are transferred to the respite center, where volunteers and staff help coordinate travel. Any who test positive, though, are then provided with a hotel room where they quarantine until they test negative. Often, entire families stay together even if only one has tested positive. They are provided with meals and any necessary medication. It’s not a prison; one family left quarantine recently and went to a fast-food restaurant. But it is an effort to both identify and treat the virus as recommended.

“The dynamics, the scope of the work changes day-to-day,” Riojas said, despite the influx of migrants stretching back to 2014. This week, for example, the city and county shifted the initial processing center from the middle of McAllen to a park in Mission, Tex. This prompted a statement about the coronavirus protocols that were in place — and spurred the news articles about those 7,000 cases the city had seen.

The context is important. That figure applies since mid-February. In the past week, the statement indicated, there had been 1,500 positive tests. But, of course, that’s in a population of people that’s being tested almost universally, a point made by American Immigration Council’s Aaron Reichlin-Melnick, the organization’s policy counsel.

“Migrants are in many ways the most tested group in the country. No other group of people in the entire country is being tested at a near-100 percent rate,” he said by phone. “So when we talk about infection rates of migrants, what we actually know is that a lot of people who are testing positive are asymptomatic; who, if they were in the United States, would have just never been tested.”

Those become the positive tests that Cruz gets to talk about on Fox News. But, despite his claim, they’re not 7,000 covid-positive people who’ve been walking around the city since February. After their positive tests, they are asked to quarantine (as quietly mentioned in Fox News’s article) and, once healthy, continue on to their final destinations.

Victor Rivera is executive director of Loaves and Fishes of the Rio Grande Valley, a homeless shelter that helps Catholic Charities by providing additional beds for migrants. In a phone call with The Post, Rivera said that he took coronavirus precautions seriously given the nature of the facility and because “I have a family, I have children.”

“Border Patrol and ICE, they are overwhelmed, there’s no doubt about that,” Rivera said. “But they do, I have to say, a pretty well, you know, system in testing them there before they do bring them to us. And so, I mean, I personally feel confident in how they are handling it.”

No one claimed that every migrant who crossed the border was tested or that every covid-positive individual was detained. But, as Reichlin-Melnick pointed out, there’s no one testing the occupants of the hundreds of thousands of passenger cars and trucks that cross into the United States at the Brownsville port of entry, either.

In June, there were 8.3 million passengers in personal vehicles who crossed the border from Mexico into the United States. There were 1.1 million trucks and 2.2 million pedestrians. And then there were about 34,000 apprehended migrants who were released from CBP custody and, often, tested for the coronavirus.

Which seems like a more likely conduit for new coronavirus infections?

Misunderstanding where the pandemic is surging

The most obvious point we can make is that the current surge in coronavirus cases doesn’t overlap with the surge in immigration or with the locations where those immigrants end up.

To the first point, the surge in new cases began in late June. The increase in immigration began in March. Meaning that, for the first three months of the current surge in apprehensions, coronavirus cases in the United States were going down.

But then there’s the geography. The places that are hardest-hit by the virus at this point are mostly not along the border with Mexico. Instead, they’re on the Gulf Coast, in Florida and stretching north from Louisiana up through Arkansas and Missouri.

The response to this is often that migrants leave CBP custody and are then transported elsewhere in the country. Often this is depicted as being done by the Biden administration. It is the case that detainees are transferred by government agencies to different facilities, as one would expect in a circumstance where centers at certain places along the border are overwhelmed.

But most migrants who are released from custody determine their own destinations, often seeking to head to places where other emigrants from their native countries live.

“Migrants are going where their families are and where their loved ones are,” Reichlin-Melnick said. “They are not being transferred to specific places at the command of the federal government.”

Of the 10 counties that are currently experiencing the highest rates of new infections relative to population, eight are more densely White than the United States as a whole and nine are less densely Hispanic. That doesn’t suggest that they are likely destinations for migrants.

What the places that are seeing high rates of infection do have in common is that they have populations that are generally less heavily vaccinated. Analysis of county-level data aggregated by the New York Times and vaccination data from the Centers for Disease Control and Prevention show that the counties that have seen the highest percentage of their populations vaccinated still have far lower rates of new infections. In fact, even more than a month into the surge, the level of new infections in the most-vaccinated counties is still below the rate of new infections in less-heavily-vaccinated counties two weeks ago.

As we’ve seen repeatedly, vaccination rates also correlate with politics. So places that voted more heavily for Trump last year generally have lower vaccination rates — and higher per capita cases.

This is key. Part of the reason that immigrants are being targeted as vectors for the spread of the coronavirus is that public health experts are identifying a more obvious cause: a lack of vaccinations. Since opposition to vaccination overlaps with opposition to preventive measures like wearing masks — and since wearing masks has been politicized by Republican elected officials as an infringement on personal freedom — there’s a motivation to find some other scapegoat for the surge in cases. There’s a reason the unvaccinated were a lot more likely to blame “foreign travelers” than the unvaccinated for the surge.

And there’s a reason that Ted Cruz and Sean Hannity did the same. It’s much easier for them to say that the increase is a function of immigrants than it is to blame Republican voters and Fox News viewers. But it’s obviously not true.