The Trump administration’s policy of separating parents from their children at the border has generated widespread outrage, lies and false reports about the origins of the policy (or whether it’s a policy at all) and some support from those saying it bolsters the United States’ commitment to the rule of law.

Over the last few days, senators have breathlessly reported from border crossings, a group of lawmakers toured a migrant detention facility in San Diego and the White House has scrambled to address the criticism.

We put together this FAQ to explain what’s behind the policy, how it’s playing out in San Diego and what to look for next as the policy continues to test the courts and the public’s patience.

Why are families being separated at the border?

In early April, Attorney General Jeff Sessions announced a “zero-tolerance” policy, meaning the federal government will try to criminally prosecute everyone who crosses the border illegally.

Before the policy was enacted, federal prosecutors in California prioritized prosecuting those caught crossing illegally who had a criminal history in the United States, or who had been caught illegally crossing multiple times. Those caught crossing illegally for the first few times, or who had no criminal histories, would simply be dealt with by immigration officials.

Prosecuting everyone includes parents who arrive at the border with their children. Since parents are being taken into criminal custody, their children cannot stay with them, resulting in the separation of families.

Family separation did happen on occasion before the “zero tolerance” policy went into effect, but far less frequently. It would happen if immigration officials questioned whether an adult with a child was actually the parent or legal guardian, if there was suspected child abuse or if the parent was referred for criminal prosecution.

An increase in separations became noticeable in 2017, as first reported by the Houston Chronicle. A memo obtained by the Washington Post confirmed that Homeland Security officials had tested out a pilot of the “zero-tolerance” policy between July and November 2017 in Border Patrol’s El Paso sector, which stretches from western Texas through New Mexico.

Soon after, cases like these Central American fathers and this Congolese mother separated from their children after arriving at San Diego ports of entry spurred lawsuits challenging family separation.

Are families legally seeking asylum being separated?

No matter how someone enters the country, he or she has the right to ask for asylum – a legal status granted to people fleeing violence or persecution.

But if they enter the country illegally – instead of at an official port of entry – they can still be prosecuted for illegal entry, and can continue an asylum claim after going through criminal proceedings and possibly serving a sentence.

Still, even families that follow the proper procedure of seeking asylum at a port of entry are being separated on occasion, though it happens less often than when families cross between ports of entry. The lawsuits involving the Central American fathers and a Congolese mother are both documented cases in which families seeking asylum were separated after arriving at San Diego ports of entry.

In December, KPBS profiled the Central American fathers who were separated from their children at the San Ysidro Port of Entry.

In those cases, officials said that they separated the families because they had reason to believe that the children were not actually related to the adults. But in one of the lawsuits, filed by the American Civil Liberties Union, immigration officials only conducted a DNA test after the lawsuit was filed and after the Congolese mother at the center of the complaint had been separated from her 7-year-old daughter for four months.

Affidavits in the ACLU lawsuit from other parents state repeatedly that when children were separated from their parents, the parents were never told it was because there were concerns over the biological relationship or safety of the children.

An El Salvadorean mother who sought asylum at the San Ysidro Port of Entry was separated from her two sons by U.S. officials, NBC San Diego has reported.

Reports like this one from Texas Monthly and this one from the Intercept show instances in which Customs and Border Protection officials have deterred asylum-seekers from arriving at official ports of entry, leading potential asylum-seekers to camp out on the streets in Mexican border towns as they wait for a chance to enter. Many of those reports have come from Texas, but backups and delays have also been known to happen at the California border.

Back in 2016, officials at the San Ysidro Port of Entry said they had a backlog that kept Haitians migrants and other asylum-seekers stuck in Tijuana for days.

Officials say the delays are a result staffing and resource limitations, but many advocates disagree.

One lawsuit filed in July 2017 alleges that CBP officials have been unlawfully deterring asylum-seekers even since the previous administration. Five of the six plaintiffs in that case came from either the San Ysidro or Otay Mesa ports of entry.

How do children and parents reunite?

This is one of the biggest uncertainties surrounding the practice of separating parents and children.

There doesn’t appear to be a good system in place to reunite parents and children who’ve been separated at the border. And even the system the government says it has in place appears difficult to maneuver given the circumstances of detained migrants, who face language barriers and have limited phone access while in custody.

Once children are separated from their parents, they are placed into the custody of the Office of Refugee Resettlement, where they either stay in a government facility or are released to a sponsor, usually a relative. They also begin an entirely separate legal immigration proceeding from their parents.

Several reports document instances in which a parent has been deported without being reunited with their child, like these from the Houston Chronicle and the New York Times.

The New Yorker follows one advocate who tried to track down a little girl on behalf of her family, revealing how difficult reunification can be.

A federal defense attorney representing one father who was separated from his daughter in San Diego told me that even he – the attorney – was only able to find the daughter with help from the local ACLU. When describing the back-and-forth required to explain to the child’s mother in Guatemala what was required to send the daughter back to her, the attorney told me there was trouble figuring out how to translate the word “fax” to the mother because of her education level and exposure to technology. That complicated the effort to send a required letter from family members saying they wanted her back.

What do we know about what’s happening specifically at the San Diego border?

What’s happening here isn’t too different from the stories we’ve seen in Texas, but for now it seems that there are fewer prosecutions and resulting family separations than in Texas. Still, they’re happening more than we’ve seen locally before.

The Southern District of California, the federal court that covers San Diego, doesn’t have a program or system in place to prosecute as many individuals as, say, Texas. While the federal court here has seen hundreds of cases a week, federal courts in Texas have been seeing thousands. That could change, though, if Operation Streamline – a program to expedite criminal prosecutions of migrants – is implemented here.

There are also fewer people crossing between ports of entry here. So far in fiscal year 2018, the San Diego sector saw 1,996 family unit apprehensions, while the Rio Grande sector saw 36,745.

San Diego County is home to three facilities for unaccompanied minors, where the Office of Refugee Resettlement houses children who show up at the border alone and children who have been separated from their families. Those facilities are small compared with the former Walmart in Texas that can hold up to 1,500 migrant children.

One of the facilities in El Cajon opened its doors to reporters Friday. Here are the accounts from KPBS and the Union-Tribune.

What is happening next?

Trump is trying to use the “zero-tolerance” policy and the resulting family separations as leverage for immigration policy changes, including funding for a border wall, reports the Washington Post. Trump has even falsely blamed Democrats for breaking up families at the border.

Every Democratic senator has signed onto the Keep Families Together Act, a bill introduced by California Sen. Dianne Feinstein to stop family separations, and several similar Democratic bills have been introduced in the House, though Democrats are the minority in both chambers. Republican Sen. Ted Cruz said on Monday he also plans to introduce a measure to end family separations.

The policy is also being challenged in court. The ACLU’s lawsuit involving the Congolese mother, has moved forward, though federal Judge Dana Sabraw, who heard the case, said he would decide later as to whether he would halt the practice nationwide.

Sabraw wrote in an order that the allegations in the lawsuit “sufficiently describe government conduct that arbitrarily tears at the sacred bond between parent and child. … Such conduct, if true, as it is assumed to be on the present motion, is brutal, offensive, and fails to comport with traditional notions of fair play and decency.”

How can I get involved?

Slate has an extensive list of organizations doing legal and humanitarian work at the border.

The New York Times editorial board denounced family separation as “immoral,” and included calls to action for those who wish to oppose the policy.

If you’re interested in speaking with your congressional representatives about the policy, phone numbers for members of the San Diego delegation are listed below. If you’re not sure which member of Congress represents you, this tool can help.

Another way to weigh in on the family separation policy is by voting: Feinstein, Davis, Hunter, Peters and Vargas are all running for re-election in November.

Sen. Dianne Feinstein

202-224-3841

Sen. Kamala Harris

202-224-3553

Rep. Susan Davis

202-225-2040

Rep. Duncan Hunter

202-225-5672

Rep. Darrell Issa

202-225-3906

Rep. Scott Peters

202-225-0508

Rep. Juan Vargas

202-225-8045