The family separation crisis has officially passed its peak. More than half of the families once separated have been reunited; the number of remaining separated families has fallen from thousands to hundreds, and is likely, under judicial supervision, to continue falling.

But family separation was always only the tip of the iceberg. It was one tactic in a broader strategic battle the Trump administration has been fighting since the days after Donald Trump’s inauguration.

The administration’s ultimate goal is to radically reduce the number of people coming into the US without papers to seek asylum here.

Seeking asylum in the US — with or without legal status — isn’t illegal. And any efforts to deter people who are fleeing violence from seeking safety are likely to result in some legitimate victims of persecution being sent back to danger, in violation of international law.

Over the past decade, that’s become an increasingly common situation facing Border Patrol agents, as a skyrocketing number of people have sought, and passed, the screening interviews that constitute the first step in the asylum process.

For the Trump administration, that makes asylum policy a vulnerability — a “loophole” — that needs to be tightened or closed.

After the end of family separation, the Trump administration’s fight is moving to the US border itself and beyond.

Family separation was a highly visible policy. The next phase in the war on asylum could be invisible to anyone who isn’t already looking for it.

Indeed, it’s already happening. From May to June, the number of people admitted legally at official border crossings to seek asylum plummeted by 42 percent. Lines stretched for days or weeks at several of the most popular crossings as the Trump administration restricted legal entry while cracking down on asylum seekers who entered illegally.

The actions Trump is taking — and those he could take — could test the strength of international principles that have existed since World War II, and the US’s membership in a community of nations that accept an obligation to save people, regardless of their citizenship, from danger. And, of course, for asylum seekers themselves, it could literally be a matter of life or death. Here are answers to nine essential questions about Trump’s ongoing war on asylum.

1) What, exactly, is asylum?

The commonsense bedrock of immigration control is this: No one should be in the US whom the US hasn’t authorized to be there.

At the same time, though, the US is under a humanitarian obligation, under its own law as well as international law, to adhere to a principle called non-refoulement: It is not allowed to force someone fleeing persecution to return to a place where she is in danger.

Fundamentally, that means that some people who do not have legal permission to enter or stay in the US should be allowed to enter or stay here anyway, because to send them back would be to endanger them, violating non-refoulement.

Asylum is the way countries reconcile the two principles. It’s a legal status that a government gives to people because they’ve been persecuted or are at risk of persecution in their home countries.

The principle of granting asylum was laid out by the United Nations in the 1951 Refugee Convention, and ratified permanently in the 1967 Refugee Protocol (which the US signed in 1968). The US’s own asylum system is governed by the 1980 Refugee Act passed by Congress and signed by President Jimmy Carter.

The UN doesn’t always agree with how the US implements its asylum system — it doesn’t, for example, believe it’s appropriate to detain asylum seekers — but there’s never been disagreement over the bedrock principle that people ought to be able to seek protection from persecution by fleeing to another country, even if they don’t have papers when they arrive.

2) How can you seek asylum in the US if you don’t have legal permission to come here?

There are two ways to come to the US to claim asylum without having papers. One is to approach the US at an official port of entry, like the one on the end of the El Paso-Ciudad Juarez bridge in Texas, and present yourself to agents of Customs and Border Protection’s Office of Field Operations.

The other way is to cross into the US between ports of entry — i.e., illegally — and, once you’re caught by a US Border Patrol agent, say you’re seeking asylum. The asylum claim is still legal, but you’ve committed a crime (illegal entry) to make it.

In either case, federal law and regulations specify that anyone who comes to the US without legal status is supposed to be asked whether she fears persecution in her home country. If she says no, she’s probably subject to expedited — all but immediate — deportation. If she says yes, she’s automatically scheduled for an interview with an asylum officer.

That interview, called a “credible fear” interview, essentially acts as a screener for asylum seekers. The asylum officer’s job is to determine a) whether the asylum seeker’s fear of persecution is a credible one, and b) whether it is likely to meet the standards of persecution set out in US asylum law.

If the asylum seeker passes her credible fear interview — as most tend to do — she’s supposed to be put into standard immigration court proceedings, in front of an immigration judge, to plead her asylum case more fully. (Immigrants who are apprehended in the interior of the US are by default entitled to an immigration court hearing, but the only way for an immigrant apprehended at the border to get there is to pass a credible fear screening.)

That hearing often doesn’t happen for several more months or even longer, due to the massive immigration court backlog and the fact that it can take up to 50 hours for a lawyer to pull together a solid asylum case.

In the meantime, the government often releases an asylum seeker from detention — either on its own volition or because a judge has ordered the government to allow the asylum seeker to post bond.

If an asylum seeker fails the credible fear interview, she has the opportunity to appeal the denial to an immigration judge; if the judge finds she should in fact qualify for credible fear, she gets a full immigration court hearing as well. If she fails review, she’s out of options and liable to get ordered deported.

3) Why has this become a prominent issue in the past few years?

Way fewer people have been entering the US without papers over the past few years than have in the past. But the people who are coming in now aren’t the same type of migrants the US saw in the decades of highest unauthorized migration.

The stereotype of an unauthorized immigrant is still a single man from Mexico in the US to find work, but that stereotype describes exactly the sort of migrant who isn’t coming into the US much anymore. Instead, border crossers are:

More likely to come from Central America — in particular, the Northern Triangle countries of Guatemala, Honduras, and El Salvador. In 2017, more than 50 percent of all migrants apprehended crossing the border were Central American.

More likely to come in “family units” (at least one parent or guardian with at least one child under the age of 18) or as “unaccompanied alien children” (below the age of 18 without a parent or guardian). Over the first six months of 2018, almost a quarter of all apprehensions were members of family units — up from 10 in 2015 — and 37 percent of all apprehensions were either family units or unaccompanied children.

More likely to seek asylum. In fiscal year 2007, asylum officers completed 5,171 credible fear interviews. In fiscal year 2016, they completed 91,786 — and 73,096 of those passed the screening.

Those three traits overlap a great deal. Family units are likely to come from Guatemala, Honduras, or El Salvador, as are credible fear claims. (In 2016, almost 80 percent of all asylum-seekers who passed credible fear interviews came from Northern Triangle countries.) So while not all families coming into the US between ports of entry, for example, are seeking asylum, a lot of them are.

These people are coming to the US for different reasons than stereotypical unauthorized immigrants of the past: They’re not necessarily seeking work, and they are likely fleeing situations in which they feel their (or their children’s) safety may be in danger.

They’re also protected, thanks to asylum law (and other legal protections the Trump administration derides as “loopholes”), from being summarily turned around or deported when they get to the US.

And while in theory Central Americans can seek asylum in Mexico rather than travel through Mexico to get to the US, the Mexican government has been accused of imprisoning, torturing, and even “disappearing” Central American migrants — and the US can’t force people to seek asylum in Mexico under current international agreements.

The bottom line is that unauthorized migration is a different policy problem than it was a decade ago. And it makes sense that it might require a different response from the government.

4) Why does the Trump administration see this as such a big problem?

President Trump has taken a radically different approach to humanitarian immigration — both asylum and refugee intake — than his predecessors. The president often seems confused about why the US is obligated to take in anyone at all — why Border Patrol can’t simply send home everyone who doesn’t have papers.

But tangled up in his general lack of a sense of obligation to take in anyone for humanitarian reasons is a more specific complaint: that the asylum system has become a way for people who don’t have valid humanitarian concerns to sneak into the US through the front door.

The heart of the problem is genuine: Even though the number of people making it into the US (at least temporarily) by passing their credible fear screenings keeps rising, the number of people who ultimately get asylum in those cases hasn’t risen to meet it at all. Essentially, the trend of the past several years has been a growth in the number of people who start the asylum process but miss the cut, or simply disappear, along the way.

This drop-off happens at every stage of the process. Less than 40 percent of people who pass the initial screening interview for asylum submit a written asylum application, for example, which is a necessary step in the process even though they’ve passed the interview and gotten assigned a court hearing.

Families seeking asylum, in particular, appear to have trouble showing up to their court hearings, which means they get ordered deported in absentia. In fact, the biggest determinant of whether a family gets a deportation order appears to be whether they show up in court.

There are lots of reasons why families could be missing their court dates. A 2018 study by Catholic Legal Immigration Network and the Asylum Seekers Advocacy Project, for example, offered suggestive evidence that families were trying to keep track of their court dates, but bureaucratic and structural issues — from inattentive lawyers to trouble getting the hearing moved to the correct location — got in the way.

The Trump administration, however, sees the drop-off rate as proof that people are using the credible fear screening to sneak into the country on the basis of asylum claims that are either fraudulent or don’t show persecution that meets the legal standards for asylum.

The administration is convinced asylum seekers aren’t just getting lost in the system — they’re deliberately disappearing because they know that if they continued to pursue asylum, their claims wouldn’t get approved. “The credible fear process was intended to be a lifeline for persons facing serious persecution,” Attorney General Jeff Sessions said in an October 2017 speech to immigration judges. “But it has become an easy ticket to illegal entry into the United States.”

5) Are the current wave of asylum seekers making legitimate claims or not?

The administration isn’t simply claiming that everyone is lying and that they’re not facing any danger or violence in Central America at all. That would be foolish. The Northern Triangle countries have some of the world’s highest murder rates, and Donald Trump has made Central Americans gangs a national boogeyman.

Instead, administration officials are pointing out that asylum law doesn’t require the US to take in anyone who might be suffering in their home country. There are limits to what, exactly, counts as persecution — or at least as persecution worthy of protection under the cover of US law.

Most people migrate for a mix of reasons: economic need, family unity, physical safety. But “persecution” only really fits in the last category.

Specifically, to qualify for asylum in the US, asylum seekers have to show that they are being persecuted on the basis of their ethnicity, nationality, religion, political opinion, or “membership in a particular social group.” And traditionally, that persecution is supposed to be at the hands of the government — or at least, something the government is unable or unwilling to prevent.

A lot of asylum claims from Central Americans in particular aren’t based in being persecuted by a government — they’re from people who were in danger due to gang violence or domestic violence.

Immigration courts (and federal courts) have spent the past several years fighting over the circumstances in which gang or domestic violence victims qualify as members of a “particular social group.” Because it wasn’t clear-cut legally, though, asylum officers tended to err on the side of allowing victims of domestic and gang violence to pass their credible fear interviews and allow the immigration judges to sort out their cases.

In June 2018, Sessions stepped directly into this debate. He issued a new precedent for the Board of Immigration Appeals — the quasi-appellate body overseeing the immigration courts — that declared that, generally, domestic and gang violence would not be able to serve as the basis for an asylum claim.

The practical effects of Sessions’s ruling are still playing out as the guidance is implemented. But it could be massively influential, precisely because it doesn’t fit neatly into the way persecution has been defined to the letter of US law to date.

US asylum laws “were never intended to provide asylum to all those who fear generalized violence, crime, personal vendettas, or a lack of job prospects,” Sessions argued in the October 2017 speech. “Yet, vague, insubstantial, and subjective claims have swamped our system.”

6) How does family separation fit into Trump’s broader asylum policy?

For the first year and change of the Trump administration, its solution to the “problem” of asylum seekers entering the US without papers was to detain them as aggressively as possible — to prevent them from slipping into the US and to send a message to would-be future migrants that they would not be welcome here.

They expanded the use of detention for all asylum seekers. They increased prosecutions of asylum seekers for illegal entry. They sought to expand the use of family detention. And finally — with a pilot program in summer 2017, and a full rollout in spring 2018 — they launched a full “zero tolerance” prosecution policy that entailed prosecuting parents who came to the US with their children, and separating parents from children in the process.

The fact that these policies were so harsh to asylum seekers was absolutely part of the plan. Despite the comments made by some congressional Republicans after family separation ended as a widespread policy, separating families wasn’t an unintended consequence of the administration’s actions. It was central to the intended deterrent effect.

“We’ve got to get this message out,” Sessions said in a June interview. “If people don’t want to be separated from their children, they should not bring them with them.”

The problem is that it didn’t work.

All available evidence at the time suggested it wouldn’t work. Prior studies of Central American asylum seekers had shown that the possibility of punishment was already factored into their decisions to come to the US; previous attempts to use harsh treatment of current asylum seekers to deter future ones hadn’t actually decreased the flow. Yet government officials were reportedly surprised when family separation didn’t lead to a noticeable drop in family apprehensions.

Meanwhile, harsh-treatment-based crackdowns ran into legal trouble; judges routinely found that asylum seekers were supposed to be treated based on the particulars of their own case, not as a threat to others. And there was, of course, a massive political backlash within the United States to the widespread separation of families for seeking asylum without papers.

The Trump administration is still seeking, in particular, to expand family detention. But it’s clear that an asylum crackdown that requires allowing people into the US and then treating them harshly offers serious political drawbacks for little policy benefit.

7) Is getting the asylum process to run more quickly a win-win solution?

It’s never possible to design an asylum policy that allows in literally every single deserving person without letting in a single undeserving one. The question is which kind of error is a bigger issue. Human rights advocates are deeply concerned about anything that could block genuine victims of persecution; the Trump administration is more concerned about letting people through who don’t qualify as persecuted under US law.

If you know that many people entering the asylum process ultimately won’t be allowed to stay, but you can’t reduce the number of people allowed to enter the process at all, the alternative is make the process run more quickly and efficiently. Changes to the process also carry less risk of political backlash; after all, it’s harder for the public to notice when people are being deported quickly or not allowed to enter at all.

But immigration lawyers are deeply concerned that any attempt to expedite the process is going to make it harder for immigrants to put together an asylum case — even if they really are being persecuted. Understanding the legal standards for asylum and collecting the evidence needed to prove persecution isn’t necessarily something an immigrant can do on her own; it takes lawyers about 50 hours to put together a single case.

The more quickly immigrants are being shoved through the system, the less likely they’ll get access to a lawyer at all, much less that any lawyer they can speak to will have 50 hours available before the judge has to rule on their case.

And if they’re not even allowed to enter the United States to plead their asylum case, lawyers won’t know about them at all.

It would be extremely likely that the US was violating the non-refoulement principle in at least some cases, and sending victims of persecution back into danger. But no one capable of holding the US government to account would know.

8) Is the administration succeeding yet?

Sessions and other Trump administration figures have made it clear that their preferred solution is to raise the standards for passing an initial credible fear interview so there aren’t so many immigrants passing their screenings.

In February 2017, the administration issued new instructions to US Citizenship and Immigration Services asylum officers — the ones who conduct credible fear interviews — that advocates worried would tighten the credible fear standards. But while credible fear approval rates dropped somewhat (to around 70 percent) in the spring and summer of 2017, they ultimately rebounded to past levels.

In his June ruling in Matter of A-B-, restricting asylum for victims of gang and domestic violence, Sessions made it clear that he wanted the same standards to be used for credible fear screenings as well — ending the practice of allowing an asylum seeker to pass a credible fear screening even if it was unclear if her gang persecution would ultimately qualify her for asylum.

Early indications are that the tightening standards might be working; anecdotal evidence suggests that asylum officers have gotten stingier in approving asylum seekers after interviews.

Asylum seekers who don’t pass those screenings are having a much harder time getting a judge to approve their credible fear claim on review. From November 2017 to June 2018, according to a July report from the Transactional Records Access Clearinghouse at Syracuse University, the approval rate for judicial review of credible fear claims fell from more than 35 percent to under 15 percent.

That shift was likely the result of new “performance standards” Sessions set for immigration judges in January 2018, which instructed them to complete most credible fear reviews within seven days.

It is possible that the combination of tighter standards for asylum officers and more pressure on immigration judges will work to cause fewer people to be allowed into the US to fully apply for asylum — and allow more people to be deported in an expedited fashion, alongside everyone who comes to the US without papers and isn’t seeking asylum at all.

But it’s also possible that the Trump administration won’t be satisfied unless it can radically reduce the number of people allowed to come to, or stay in, the US.

9) What other options does Trump have to crack down on asylum?

The administration could continue to make incremental moves to speed up the process (by hiring more immigration judges, for example) or tighten the credible fear standard (by, for example, finalizing a regulation currently being drafted that would make it hard for someone to qualify for asylum if they’d entered the US illegally).

But from the philosophical standpoint of “border security,” the ideal solution would be one that allowed the US to stop people from setting foot in the US to seek asylum at all.

The US could do this with Mexico’s help. Administration officials have made it clear that they’re hoping to sign a “safe third country” agreement with Mexico, which would declare that the US considers Mexico a safe enough country to seek asylum in — and therefore would allow the US to turn back anyone who crossed through Mexico to seek asylum here. (The US already has one of these with Canada, which is why Canada is legally prevented from accepting migrants fleeing the US.)

Alternatively, it could (either with or without Mexico’s permission) start requiring asylum seekers to go back to Mexico after making their asylum claims and wait there until their claims were processed.

Or the Trump administration could act on its own to do what Trump appears to want: seal the border to asylum seekers entirely.

The US is quietly engaging in a moderate version of this. For the past few months, asylum seekers coming to official ports of entry — in other words, seeking to follow the law — have been told that there isn’t room to process them. Some have been waiting in the hot summer sun for weeks at a time outside ports from San Ysidro, California, to El Paso, Texas.

At one port, asylum seekers themselves have kept records of who is next in line because the government hasn’t created a system. In a couple of incidents in June, a Customs and Border Protection agent physically prevented asylum seekers from setting foot on US soil — thus depriving them of the legal ability to claim asylum.

Overall, according to a report issued by the Washington Office on Latin America (a left-leaning policy group), “the number of unaccompanied children and family members admitted to the ports of entry, mainly for protection requests, plummeted by 42 percent from May to June.”

The number of children and families apprehended between ports of entry decreased only 8 percent over that time — indicating that the 42 percent drop wasn’t simply a matter of fewer people trying to come to the US, but an active restriction on the part of the Trump administration.

Trump could go further, and limit, or eliminate, the ability of asylum seekers even to present themselves at ports of entry. Customs and Border Protection has denied a report in the New York Times in July that the administration was considering preventing anyone from applying for asylum at the border.

But sources indicate to Vox that other plans under discussion would allow the government to “reclassify” certain ports so that they no longer accept foot traffic — thus preventing them from being legally accessible for asylum seekers on foot.

The further Trump goes to unilaterally shut down the border, the more likely it is that he engages in what lawyers and the UN Office of the High Commissioner for Refugees would consider clear-cut violations of international refugee law. But international condemnation wasn’t enough to get the administration to end family separation at the border — it took a domestic political backlash to do that. Out of sight of the American public, who knows how far the Trump administration could go.