President Trump on Saturday justified his executive order suspending the US’s refugee admissions program on national security grounds, calling for a more thorough form of “extreme vetting” to replace the current screening regime in order to better determine whether a refugee poses a danger to the country.

But the reality is that the current vetting system is already pretty extreme: exhaustive, loaded with safeguards, enormously selective, and constantly being improved. It typically takes 18 to 24 months, but it can last as long as three years. It’s difficult to conceive of what kind of extra steps could be added to make it even more extreme.

What is clear is that Trump’s approach to reforming the vetting system is extraordinarily harsh. His executive order bans all refugees from entering the US for 120 days, and Syrian refugees indefinitely. It also more than halved the ceiling for refugees who will be allowed into the US this fiscal year, reducing it from 110,000 to just 50,000.

So far, around 30,000 refugees have been let in this fiscal year (which began in October 2016 for the federal government). But it’s unclear how many more — if any — will be let in if Trump extends the refugee ban or makes the vetting process selective to the point of being entirely impenetrable.

Trump’s refugee suspension is a solution in search of a problem

Trump’s defense of the executive order — which includes, most controversially, a 90-day ban preventing foreign nationals from seven majority-Muslim countries from entering the US — has been that it’s necessary to protect the country from nefarious foreigners who want to use the refugee program to sneak into the US and launch terrorist attacks.

Our country needs strong borders and extreme vetting, NOW. Look what is happening all over Europe and, indeed, the world - a horrible mess! — Donald J. Trump (@realDonaldTrump) January 29, 2017

But the current system in place is designed to prevent exactly that, and it has many extra layers of security for refugees from Syria and other countries where groups like ISIS and al-Qaeda are most active.

Mousa Almshhad, a 39-year-old refugee from Syria who was resettled with his family last year in Baltimore, said that his refugee resettlement process entailed being interviewed four or five times, with about two to two and a half months in between each interview.

“I do not think there’s a single question about my life that they didn’t ask about”

“The questions were not just questions — they were interrogations that were being back by investigations,” he told me in a phone interview, speaking through a translator because he doesn’t speak English. “They really cared about knowing about all the details. Each question led to another hundred questions. I do not think there’s a single question about my life that they didn’t ask about.”

Almshhad, whose wife and 14-year-old son were interviewed separately from him, said the interrogations often involved being asked the same questions over and over again, but in different ways, with the goal of fact-checking and spotting slight inconsistencies.

“I was telling the truth the whole time, so my story was straight, but other people who had slipped up and given different details were rejected on the spot,” he told me.

“I was asked questions you could not believe and could not think of, and even asked questions about my life that I did not know the answers to,” he said. “They even asked about one of my uncles who was dead for a couple of questions.”

The intense investigation that Almshhad underwent in order to be admitted to the US was not unusual. The arduous vetting process involves investigations by a coordinated network of US law enforcement and intelligence agencies, all actively looking for any indication that an individual could potentially pose a threat in the future.

That level of rigor is partly why not a single refugee has carried out a fatal terrorist attack in the United States since the current refugee program was put in place in 1980.

The vetting process has many steps — and tons of safeguards

The refugee admission process has evolved over the years in order to try to maximize the effectiveness of the program and ensure that it doesn’t let any potentially risky candidates slip through the cracks. I spoke with Robin Dunn Marcos, the senior director of processing and resettlement at the International Rescue Committee, to help walk me through the vetting procedure.

Step 1: The very beginning of the process usually involves an individual or family seeking refugee status through the United Nations High Commissioner for Refugees (UNHCR), the organization that oversees refugee support and protection across the world.

The UNHCR collects some initial biographical information, identifying documents, and sometimes biometric data like fingerprints. Then typically either the UNHCR or a representative from the government of the country the refugee has fled to conducts an in-person interview to determine if the person does in fact meet the legal definition of a “refugee.”

According to the UNHCR, a refugee is defined as “someone who has been forced to flee his or her country because of persecution, war, or violence. A refugee has a well-founded fear of persecution for reasons of race, religion, nationality, political opinion or membership in a particular social group.”

The UNHCR refers less than 1 percent of people who qualify as refugees for resettlement in a third country like the United States. There are currently 26 countries that actively participate in refugee resettlement, and historically the US has been the leader, generally accepting more than half of the world’s refugees referred to a third country.

Yet the US is also home to fewer refugees per capita than many other affluent nations. For example, according to 2015 end-of-year data from the UNHCR, Sweden had 17 refugees per 1,000 inhabitants, France had 4.2, the UK had 1.9 — and the US had 0.8. In the past several years, the ceiling set for refugee arrivals in the US has hovered somewhere around 60,000 to 70,000 refugees a year, with a spike in 2016 to 85,000 as part of a bid by the Obama administration to take in more Syrian refugees.

Step 2: After the UNHCR has referred a refugee to the US for potential resettlement, the applicant’s information is sent to a Resettlement Support Center. These are international agencies or nonprofit organizations contracted by the US State Department — such as the International Organization for Migration or Church World Services — to interview the refugee and compile the personal data and background information needed for US security clearances and interviews.

They also kick off the first security clearance process by checking the refugee’s name against a global database to see if the person had applied for a visa or other immigration benefits before, which, if they had, would be flagged and reviewed.

Step 3: After that, the main security check begins — a screening process more extensive than for any other kind of person entering the US, such as someone traveling on a student or business visa.

A network of US law enforcement and intelligence agencies including the FBI, the State Department, the Department of Homeland Security, and others screen and investigate the applicant using the information from the Resettlement Support Center. They look at things like the refugee’s criminal background, possible connections to groups the US considers a threat, family relations, travel patterns, cellphone records, social media presence, and more.

This interagency security investigation continues in the background throughout the rest of the vetting process. If any new information about a refugee emerges, whether through subsequent interviews or because they did something like register a new email address or get a new phone number, it will be end up being scrutinized through the ongoing security screening program.

Step 4: People coming from conflict zones and terrorist hot spots — such as Iraq and Syria — are then subjected to an extra layer of security checks. The US errs heavily on the side of caution with Syrians; in 2015, the Department of Homeland Security said the US only took in about one-tenth of the Syrian applicants referred by the UN.

Step 5: If the applicant clears all of those screenings, a specially trained officer from the Department of Homeland Security travels to the country where the refugee is currently living in order to interview them in person, to make sure both that their claim to being a refugee is valid and that they are admissible under US law — making sure they weren’t involved in persecution of others in their home country, providing material support to terrorists, and so on.

During this process, fingerprints and photographs are taken as well. Their fingerprints are then cross-checked against various biometric databases, including the FBI biometric database; the DHS biometric database, which includes terrorist watch list information; and the Defense Department database, which includes fingerprints that have been obtained around the world.

There’s also a medical screening conducted, to make sure the refugee is fit for travel and to identify any diseases that could affect public health in the US.

Step 6: Next, the refugee is matched up with one of nine domestic sponsoring agencies in the US that work with the State Department to help the refugee settle somewhere in the US. Most (though not all) of these sponsoring agencies are faith-based organizations, and they have about 300 offices across the country in total.

Refugees are provided with a cultural orientation session that lasts a few days and then matched with housing and provided with a modest stipend to help them adjust in their first three months to start their new life in the US. Agencies also help place them in a job, but encourage them to become economically self-sufficient as swiftly as possible.

All along the way, the resettlement agencies are expected to report any suspicious activity they see to the government — for example, if a man abandons his family shortly after arriving in the US. Refugees are also required to report any change of address to DHS within 10 days.

The vetting process is always evolving

The refugee vetting process has been internally evaluated and improved over the years in order to identify potential gaps. For example, in 2008 the family reunification program for refugees was suspended after widespread fraud was discovered among refugees from East Africa who claimed they were related because they thought it would boost their odds of selection.

The program was reinstated again in 2012, but with additional safeguards, like DNA testing or a requirement of official adoption papers. Family reunification has gone from being responsible for 15 to 20 percent of refugee arrivals in the 1990s to less than 1 percent today as a result. (There is, however, legitimate concern that the requirement probably poses some insurmountable obstacles for some adoptive families.)

“Refugees are the most vetted group of entrance into the United States,” says Dunn Marcos. “It’s easy to take pride in the program because it is continually strengthened.”

Trump has yet to provide any concrete details about what he means by “extreme vetting.” So far, it’s just the temporary ban.

But given the measures already in place, it’s far from clear how it could be improved dramatically without resulting in a complete stoppage of any refugees coming in at all. Perhaps that’s the goal.