President Biden is under mounting pressure from both the left and right on immigration, the issue on which his polling numbers are worse than any other.

Progressives and human rights groups want to see Biden move faster to dismantle the last vestiges of former President Trump’s approach — particularly in relation to a controversial measure that allows U.S. authorities to turn back would-be refugees on public health grounds. 

But Republican politicians and conservative media are branding a sharp increase in attempted crossings of the southwestern border as “Biden’s border crisis.” They say that the president’s approach is encouraging illegal migration attempts and thus ceding control of the nation's frontiers.

When Homeland Security Secretary Alejandro Mayorkas testified before the House Appropriations Committee Wednesday, he came under a hail of critical questioning from GOP lawmakers.

Rep. Chuck Fleischmann (R-Tenn.) asked Mayorkas whether the Biden administration was sending the “message to one and all … that this country will not enforce its immigration laws?” 

Rep. Steven Palazzo (R-Miss.) claimed that the White House had “rolled out a big welcome mat” for anyone who wanted to cross the border.

Mayorkas disputed both those claims. But there is little doubt that immigration has become a serious vulnerability for the administration.

A new Quinnipiac University poll released Wednesday found that just 35 percent of adults approve of how Biden is handling immigration issues. Fifty-two percent disapprove. 

Those figures pose a startling contrast to Biden’s marks for handling the COVID-19 pandemic. On that topic, 65 percent approve and 30 percent disapprove. 

The immigration ratings are also way below his overall job approval score — 48 percent approve and 40 percent disapprove of his performance so far. 

The poll’s more granular findings show more red warning lights for Biden. Independent voters break decisively against him on immigration, with 52 percent disapproving of how he is handling the issue and just 29 percent approving. His disapproval from Republicans on the topic is sky-high at 91 percent. And more than 1 in 5 Democrats, 22 percent, also disapprove.

It seems likely that Republicans and independents believe Biden is taking too lenient an approach, but some Democrats might well hold the opposite objection.

One key point of contention for liberals is called Title 42. 

Title 42, which dates back to a 1944 law, allows authorities to deny refuge to asylum-seekers, or migrants, on public health grounds. It was invoked by Trump during the early days of the pandemic, purportedly to slow the spread of COVID-19. Its deployment is closely identified with Trump adviser Stephen Miller, known for his ultra-hawkish attitude on immigration.

The Biden administration has not yet ceased to use Title 42 in the same way — to the growing exasperation of liberals.

“It was a concocted policy by Stephen Miller to close the border using the pandemic as cover,” complained Frank Sharry, the executive director of America’s Voice, an organization that advocates for liberal immigration reform.

Sharry added: “Whatever justification the White House feels for keeping Title 42 in place, given the political pressures they have come under, is behind us. More than 50 percent of the country is vaccinated, the level of infection is way down. The idea that this is a public health imperative is at this point losing its credibility.”

Sharry insisted the administration ought to “move with alacrity” to discontinue the use of Title 42.

It is not the first time Biden has irked progressives. Just a few weeks ago, a decision to maintain a Trump-era cap on the number of refugees the nation would admit sparked furious backlash. The White House made a swift U-turn on that question.

The administration’s jumpiness on the topic is one sign that it is feeling serious political pressure.

The latest figures from U.S. Customs and Border Protection show a huge spike in attempted crossings in the southwest. 

The agency noted that encounters on the border numbered more than 170,000 in both March and April. Those numbers represent an increase of about 70 percent from 2019. (The numbers from 2020 were smaller still, though that is generally attributed to the effects of the pandemic.)

Conservatives complain that the shift in rhetoric from Trump to Biden has emboldened would-be migrants. Their ire is stoked further by reports like one which appeared in The Washington Post on Wednesday regarding ICE, the Immigration and Customs Enforcement agency.

The Post noted that ICE had 6,000 officers but that they “currently average one arrest every two months.” The story also stated that there were fewer than 3,000 deportations carried out by ICE last month, which it termed “the lowest level on record.”

Mayorkas, at his Wednesday appearance on Capitol Hill, said he did not believe the average arrest statistic was correct. 

Still, conservatives believe Biden is in practical terms acceding to the left’s desire to abolish ICE without explicitly admitting he is doing so. The Republican National Committee sent reporters an email on Wednesday asserting, “Joe Biden is functionally abolishing ICE.”

“I don’t know what else he can do to handcuff and shackle” immigration enforcement, said Ira Mehlman, the media director of the Federation for American Immigration Reform (FAIR), which supports stricter immigration laws and enforcement.

“Mayorkas has basically said he doesn’t want them to do very much,” Mehlman added. “If you have 6,000 officers averaging one arrest every two months, they become the equivalent of the Maytag repairman.”

The politics of the immigration issue are fiercely complicated. 

Polls show a clear majority of Americans favor legalizing the status of people brought to the United States as children without authorization — the so-called Dreamers. 

An ascendant left in the Democratic Party has pushed for greater liberalization generally, including decriminalizing unauthorized border crossings and providing government-run health insurance to people in the country illegally.

But those positions are far less popular than support for the Dreamers. 

Meanwhile, immigration is a subject that garners enormous coverage from conservative media outlets and is at least perceived to help motivate GOP voters to turn up at the polls.

Brendan Steinhauser, a GOP strategist in Texas, said that for conservative voters in particular, “without a doubt, border security is right up there [in importance] nationally, right behind jobs and the economy.”

Politically, he added, “I think it just does motivate the border security, ‘enforce the law’ side more. It is more of a top issue and it moves them. On the progressive side of the Democratic Party, they worry about the humanitarian side in particular but they have other issues that are a little bit more important to them.”

Leftists, for their part, lament that Democratic moderates are too resistant to trying to recast the underlying terms of the debate.

“The duty of progressives is not simply to push for change on the details of the policy. It is to really articulate a different message and different vision of who immigrants are,” said progressive strategist Jonathan Tasini. “Progressives should believe in open borders. Immigrants have never been the threat that politicians want to portray them as. They have been used as a cover for bad economic policies that have nothing to do with immigration.”

The White House is far away from even grappling with those questions. 

For now, Biden would surely be content to thread the needle between the competing political pressures he faces.

So far, it’s proving extremely hard for him to do so.

The Memo is a reported column by Niall Stanage.