The huge increase in illegal border crossings that President Biden described as “seasonal” is growing larger despite the summer heat. Americans rate his handling of immigration poorly, polls show. And the president himself worries that Republican attacks on the issue will resonate politically, according to people familiar with his thinking.

When President Barack Obama faced a similar situation, he toughened enforcement, detained families and increased deportations. But under Biden, such measures have become anathema to Democrats who feel they were badly abused by President Donald Trump.

That leaves Biden in a vise, caught between the costly reality of a historic border influx and supporters who erupt in anger when his administration hints at tighter controls.

“It’s much harder to use the same enforcement tools because they were used for such ugly purposes by the last administration,” said Cecilia Muñoz, who, as Obama’s top immigration adviser, was vilified by activists unhappy when Obama increased deportations. “The motivation of the people using the tools really matters a lot.”

Immigration is likely to flare up again as an issue in coming weeks. A federal judge on Friday partly halted a program protecting those brought to the United States as children, commonly known as “dreamers.” The administration faces mounting pressure to lift pandemic-related border controls. And the border surge shows new signs of momentum, with more than 6,000 arrests per day in recent weeks.

The White House is pursuing what even some allies regard as a muddled immigration strategy, embracing policies that make it easier for migrants to come while often deploying stern rhetoric warning them not to.

“They’ve done a terrible job of communicating it,” said Frank Sharry, executive director of America’s Voice, a group promoting immigration changes. “I’m impressed with the strategy. I’m unimpressed with the communication.”

The cross-pressures are expected to come to a head in the next few weeks as the administration faces critical decisions about how and whether to unwind Title 42, a public health order Trump invoked to swiftly return most border-crossers to Mexico during the pandemic. Immigrant advocates are pressing the White House to fully abandon the policy, but doing so could trigger an even larger border influx — and a bigger political headache.

Federal authorities have logged more than 1.1 million apprehensions at the U.S.-Mexico border this fiscal year, after more than 188,000 illegal crossings in June — a 20-year-high — prompting a fresh round of Republican criticism. About one-third of those taken into custody were repeat crossers who had been previously detained by U.S. Customs and Border Protection, the agency said.

Nearly six months into his presidency, Biden’s inability to shake off early struggles on immigration is creating growing anxiety for Democrats in swing districts and border areas who face tough congressional elections next year.

“I don’t want to beat up on the administration, but we have to make decisions that are not easy and soft,” said Rep. Vicente Gonzalez (D-Tex.), whose district includes the Rio Grande Valley, the busiest stretch for illegal crossings. “We need to be humane and treat people with dignity, but we have to have orderly process on the southern border.”

The quandary erupted earlier this year during Biden’s messy rollout of a decision to allow more refugees into the United States. The administration pressed ahead with a plan to relax Trump’s strict limits, but Biden balked as he grew concerned about the perception of allowing more foreigners in at a time his administration was struggling to manage a surge of migrants arriving on the southern border.

That hesitation prompted fury from fellow Democrats, so Biden reversed course again and agreed to lift the refugee cap after all.

The immigration issue has bedeviled presidents for decades, as Americans say they favor firm limits but also humane treatment, while Congress remains too divided to act. But Biden faces a unique challenge in following Trump, who electrified anti-immigrant sentiment on the right but at the same time energized pro-immigrant passions on the left.

Upon taking office, Biden moved quickly to relax some of Trump’s toughest policies. He ended a program that required families seeking asylum to wait outside the United States, and he stopped using Title 42 to turn away children arriving without parents or guardians.

But the basic tools of immigration enforcement — detention, deportation and strict bans on who can enter — remain stigmatized among many Democrats, and unacceptable to former activist leaders who now hold key positions in the White House.

As one former U.S. official who worked on Biden’s transition team put it, “We did the positive stuff quickly, but not the deterrence part.”

The official, who maintains close ties to the Biden team, described the president as “super concerned” about the political ramifications of the tumult at the border. “He knows the damage this can do and what a gift this is to Republicans,” said the official, who like others spoke on the condition of anonymity to describe private discussions.

In a recent Washington Post-ABC News poll, 33 percent of survey respondents said they approved of Biden’s handling of immigration while 51 percent disapproved. It was Biden’s worst-rated issue in the survey.

Biden and his aides argue vigorously that the Trump rules amounted to a destructive approach that will take time to fully unwind. “Cruelty isn’t a strategy,” said Tyler Moran, a top Biden immigration adviser who serves on the White House Domestic Policy Council.

Moran is a former executive director of the Immigration Hub, an advocacy organization that spent years battling Trump. Other advocates have also joined the administration from immigrant rights groups, such as Alida Garcia, who took a leave of absence from FWD.us in March to become a senior adviser on migration.

Moran will succeed Amy Pope as senior adviser for migration, according to a White House official. Pope, who has been seen by some as a moderating force in the White House during a temporary stint, is leaving to join the International Organization for Migration, a group she was nominated for earlier this year.

“Biden is a centrist, but he depends on his staff like any other president,” said Rep. Henry Cuellar (D-Tex.), who represents a border district and has urged the administration to toughen its approach. When it comes to immigration policy, Cuellar said, “the more ‘open borders’ vision is winning out at the White House.”

Vedant Patel, a White House spokesman, said Biden’s decision-making is “rooted in implementing an orderly and fair immigration system.”

One Biden ally noted that this policy team has been ensconced since the outset of his administration, while the heads of agencies such as CBP and U.S. Immigration and Customs Enforcement (ICE) have yet to be confirmed by the Senate. That could mean more ideological figures are in place, while relatively pragmatic ones are not.

Moran described Biden’s approach as multipronged, saying it includes “deterring irregular migration” as well as “addressing the factors that drive people to our border.” She also cited expanding protections for refugees and “returning to regular order where people are able to ask for asylum at our border.”

Administration officials also say they will reduce illegal migration by making it easier for temporary workers and immigrants’ relatives to come to the United States legally. They plan to implement a new system to expedite asylum claims. And they hope to expand the use of electronic monitoring, so migrants will not have to stay in detention while awaiting a ruling on their asylum claims.

Critics respond that such moves will do little to reduce illegal crossings as long as migrants who fail to qualify for asylum find it easy to stay in the United States anyway. Immigration arrests and deportations from the American interior are down by more than half under new Biden policies that curb ICE enforcement.

White House officials say it’s too soon to judge the effectiveness of their immigration policy. More broadly, they say the country’s immigration system will remain fundamentally dysfunctional until Congress passes major changes, a prospect that appears remote. Biden issued a statement Saturday imploring lawmakers to protect dreamers. “I now renew that call with the greatest urgency,” he said.

“The crosscurrents on immigration policy and politics are wicked,” Sharry said. “You want to get the policy right and you can only move to change the policy if the political space is either available or created.”

Republicans have seized on the rush of migrants to the border, along with a separate rise in homicides, to argue that Biden has sowed chaos and is making Americans less safe — a message that has caused some alarm inside the White House.

This past week, 26 Republican senators wrote Biden urging him not to rescind Trump’s use of Title 42, which lets the government prohibit people from entering the United States to prevent contagious diseases. “Allowing political considerations to overrule the clear public health threat created by the spread of COVID-19 at the border is reckless and irresponsible,” the letter said.

Administration officials say they are making preparations to end the provision’s use, though they have yet to set a firm timeline or procedure for doing so. “We do know that Title 42 won’t be in place forever,” Moran said.

ICE officials who were not authorized to speak to reporters say the agency has been deploying more personnel to the southern border and increasing detention bed capacity to brace for the potential impacts of ending Title 42.

The administration’s efforts to toughen up often involve using stronger language and urging other countries to do more, rather than sending more people back to their home countries.

At the State Department, Biden officials are working with Mexico and other nations to stiffen enforcement and discourage unauthorized migration with advertising and a strong message that the border is closed.

When Vice President Harris visited Guatemala last month, she bluntly told potential migrants, “Do not come.” While Biden and others in the administration have used similar language, many immigration activists were taken aback, seeing Harris’s words — coming on her first trip to Central America — as harsh and even reminiscent of Trump’s language.

Two weeks later, Harris struck a different tone when she landed in El Paso for her first trip to the U.S.-Mexico border. Harris spoke with teenagers in U.S. custody about their career ambitions and touted the administration’s improved treatment of migrants. Harris’s host, Rep. Veronica Escobar (D-Tex.), said that El Paso was America’s “new Ellis Island.”

Some experts suggest the policy of urging other countries to deter migrants is problematic.

“There is perhaps an element of hypocrisy in saying we’re okay doing heavy enforcement as long as it’s not done by us,” said Andrew Selee, president of the nonpartisan Migration Policy Institute. “In some ways it looks like we are turning over the responsibility for enforcement to Mexican and Central America border authorities, who may have less institutional capacity and human rights training.”

The alternative, many Republicans say, is a return to Trump’s hard-line policies, or at least the stepped-up enforcement favored by predecessors in both parties. Biden’s resistance to taking this path has broken a historical pattern, surprising both allies and adversaries.

“Every time the politics heats up, the administration in charge resorts to cruel deterrents,” Sharry said. “They didn’t do that.”