By Nick Miroff, Annie Linskey, Josh Dawsey, Washington Post–

Homeland Security officials thought they finally were getting a handle on the crisis at the Mexico border, after warning for months that agents and holding cells were beyond “the breaking point.”

The record surge of Central American families has started to abate. The Mexican government has launched a broad crackdown after a deal with President Trump. And in a rare example of bipartisan action, lawmakers last week approved $4.6 billion in supplemental funding, most of it to improve care for minors who arrive without parents.

Then the border crisis collided with the 2020 presidential campaign, putting the still-grim realities of U.S. border enforcement at the emotional core of the Democratic primary.

Since last week’s Democratic debates, candidates and prominent lawmakers have focused their attention on distressing photos of a father and daughter drowned in the Rio Grande, accounts from the government’s own internal watchdog of squalid conditions in border cells, and revelations of denigrating and explicit postings on social media by U.S. agents.

Meanwhile, some Democrats are questioning the basic legal underpinnings of U.S. immigration enforcement and challenging the long-held consensus that a robust detention and deportation system is necessary to prevent an even bigger flood of illegal immigrations into the United States.

On Tuesday, Sen. Cory Booker (D-N.J.) said he would “virtually eliminate immigration detention” by executive order. During last week’s debate, presidential candidate Julián Castro proposed decriminalizing illegal border crossings — a position other Democrats in the race rapidly adopted.

Others in the party are urging caution, saying the push toward decriminalization risks playing into Trump’s hands at the very moment his strategy to stem the tide of Central American migration is showing signs of progress.

“That is tantamount to declaring publicly that we have open borders,” said Jeh Johnson, who ran the Department of Homeland Security during President Barack Obama’s second term. “That is unworkable, unwise and does not have the support of a majority of American people or the Congress, and if we had such a policy, instead of 100,000 apprehensions a month, it will be multiples of that.”

In May, U.S. agents took more than 144,000 migrants into custody, the highest one-month total in 13 years, led by unprecedented numbers of parents arriving with children. The families are typically released into the U.S. interior pending a hearing in backlogged U.S. immigration courts.

The wave of newcomers left Border Patrol holding cells in high-traffic areas like El Paso and the Rio Grande Valley of South Texas crowded far beyond capacity, some so stuffed that detainees lacked enough floor space to lie down.

As the volume grew, many under­age migrants became stranded inside border stations, despite court orders mandating their transfer within 72 hours to child-appropriate shelters overseen by the Department of Health and Human Services.

But those pressures have eased in recent weeks as border-crossing arrests dropped 31 percent between May and June. The number of migrants held in Border Patrol custody has fallen nearly 40 percent since late May, according to a DHS official citing preliminary data.

On May 30, Department of Homeland Security acting secretary Kevin McAleenan said Customs and Border Protection had more than 2,350 minors in its holding cells as the HHS shelters were out of bed space. But as of Tuesday morning, CBP had fewer than 300 minors in custody, said a Homeland Security official, speaking on the condition of anonymity to disclose data that had not been authorized for release.

“We were getting 350 (minors) a day one month ago,” the official said. “Now, fewer are arriving and that is improving HHS’s ability to take them.”

As of Tuesday, the total number of detainees in Border Patrol custody was about 11,000, and a Customs and Border Protection official said the system remained in a crisis state. “A healthy number is about 4,500, spread out across the border,” the official said.

CBP has opened three large air-conditioned tents in recent weeks and, in one measure of improving conditions, is no longer holding detainees outdoors.

Rep. Joaquin Castro (D-Tex.), chairman of the Congressional Hispanic Caucus and the twin brother of Julián Castro, led a delegation to the border station in Clint, Tex., on Monday, where attorneys described children held in appalling conditions last month.

Castro captured surreptitious photos and video showing women in sleeping bags sitting on the floor of a crowded, austere holding cell. Rep. Alexandria Ocasio-Cortez (D-N.Y.) said detainees told her they were ordered to drink toilet water.

A CBP official confirmed Tuesday in an interview that the faucet was broken at the time of the delegation’s visit, but the official said there was a five-gallon water jug in the room with cups. The official said that a maintenance crew was scheduled to repair the faucet and that agents would not direct a detainee to drink from a toilet.

Joaquin Castro’s photos did not appear to depict conditions in violation of detention norms, and the holding cell in the images did not show the disorder captured in aerial photographs last month and images of children sleeping on the ground outside Border Patrol stations.

Julián Castro said in an interview Tuesday that his proposal to decriminalize illegal border crossing is a reaction to what he sees as the excessively hard-line approach of the Trump administration.

“There’s no question that many of us across the country have spoken out against the Trump administration as it has cruelly treated children and their parents who are migrants. It calls for us to offer a more strong, bold and compelling vision on immigration,” he said.

The presidential candidate dismissed any notion that critics would call his plan a step toward open borders. “I’m confident there are a lot of Americans would agree with me.

Julián Castro, a former San Antonio mayor and secretary of Housing and Urban Development under Obama, was the first candidate to release a detailed immigration plan, including a path to citizenship for 11 million U.S. immigrants who lack legal status. He also proposed eliminating U.S. Immigration and Customs Enforcement (ICE) and vastly increasing aid for Central America to stabilize the region.

The most attention-grabbing part of his plan is a provision to largely decriminalize border crossings. “Migration shouldn’t be a criminal justice issue,” Castro said.

Trump’s campaign advisers were gleeful Thursday when Democrats followed Castro’s lead and said they would support health care for those who arrive illegally — after a period when many Democrats had yet to delineate specific policy positions on immigration.

Trump has told aides he wants to seize ground on the issue — and push forward this month with plans for ICE arrests of families with deportation orders. He has prodded for a faster pace of construction on border fencing and brings up the topic regularly in meetings that are unrelated to immigration, advisers say.

“It was unanimous that Democrats running for president want to give free, taxpayer-funded health care to illegal immigrants while the prevailing argument is to eliminate private health insurance for 200 million Americans,” said Tim Murtaugh, a Trump campaign spokesman. “There is no possible way to defend that.”

Murtaugh said voters should expect the campaign and the president to talk about immigration every day for the next “489 days or so.”

“There can be no mystery of what Donald Trump’s view of illegal immigration is. His view has not, and will not, change. Borders have to mean something,” he said. “This is the same crowd that denied there was a crisis at the border, then called it a manufactured crisis and still won’t work with President Trump to solve it.”

But some of his campaign advisers note polling shows the president turns off moderate and Latino voters with his harsh language on immigration. And they fear that some of the most dramatic images, including detained children and drowning deaths in the Rio Grande, with a sense that the issue is surging out of control, could hurt the president.

“His base is already well-fed and ready to come out for him. He needs to put a doubt in his head that Democrats have gone so far to the left. This issue can be helpful to the president if it is used to make a broader point about how far left Democrats have gone. They have far overcorrected and overreacted and staked out a position that is entirely unreasonable to most people,” said Brendan Buck, who was a top aide to former House speaker Paul D. Ryan, who argued with Trump on 2018 midterm strategy.

Celinda Lake, a Democratic pollster, said that views about immigration are changing among Democratic and independent voters and that the shift is reflected in how Democratic presidential candidates are talking about immigration.

In the past, when she asked focus groups to conjure an image of undocumented immigrants, they would describe a group of men “aggressively climbing fences” and talk about taking jobs. “Now people volunteer that father and daughter who died, and parents being separated. It’s a very different image now,” Lake said. “The Democrats’ shift in perspective actually is fitting exactly with the public’s shifting in perspective, and I think it’s actually a unique moment,” Lake said.

Lake acknowledged that the issue does excite Trump’s base. “And with the exception of Republican suburban women, his rhetoric is very appealing to his base,” Lake said. “But that it is not appealing to other people.”

nick.miroff@washpost.com

annie.linskey@washpost.com

josh.dawsey@washpost.com