Syrian refugees hoping to immigrate to the United States face not only a hostile Congress but also an intense screening process that includes the collection of biometric information and a series of interviews with American security experts, a process that can take 18 to 24 months.

The U.S. House of Representatives passed a bill Thursday meant to suspend the program that enables Syrian and Iraqi refugees to resettle in the U.S., a response to the terrorist attacks that killed 130 in Paris on Nov. 13. President Obama has threatened to veto the bill, while supporters say resettlement will resume when national security agencies verify that refugees don’t pose a security threat. But the U.S. already has some of the world's toughest barriers to entry, experts say, pioneering a vetting process utilizing a military database built from a decade spent in the Middle East.

A refugee’s first point of contact upon fleeing Iraq, Syria or another war-torn nation is the United Nations High Commissioner for Refugees, which determines if the individual is fleeing his or her home country over a well-founded fear of persecution (the legal definition of refugee). The refugee is interviewed by a member of the UNHCR, who captures an iris scan that identifies a person based on the unique, complex patterns in the eye. From there, the file is passed on to representatives from the U.S. Department of Homeland Security, the State Department and a number of other agencies, who take the applicant’s fingerprints and interview them repeatedly to look for inconsistencies in their story.

“One of the best checks for security is the interview stage, when you triangulate the first and second interviews,” said Nick Micinski, a researcher focused on refugee migration and a former officer at the Migrant and Refugee Communities Forum in London. “That means if someone says they’re from Iraq and seeking asylum because they’re afraid of a certain thing, then they should have knowledge about that thing, or speak with a certain dialect. The people conducting interviews have been doing this for a very long time, and they have expert knowledge on what kinds of threats are in which areas.”

Information culled from those interviews is then screened against the FBI’s Integrated Automated Fingerprint ID System, the Department of Homeland Security’s Automated Biometric ID System (showing any previous encounters with U.S. immigration), and international terror watch lists issued by the U.S., United Nations and European Union. Depending on the crisis, refugees may go through years of interviews meant to catch any holes in their story.

Gifted Liars?

“We also ask about family information and biographical information, [not only] for their own case but also to start a record to find out who to contact if something happens to one of their family members,” said Erika Iverson, an interviewer who screened candidates throughout sub-Saharan Africa after the September 11, 2001, terrorist attacks in the U.S. “As much as people think there are gifted liars in this world -- and there are -- these are a lot of interviews that are held over a long period of time, and I don’t even know if I could answer some of these truthfully about myself. In some cases it’s like, ‘What color was your front door when you were 9 years old?’”

The conversations are primarily conducted in refugee camps along the borders of Jordan and Turkey, as well as cities like Istanbul and Mafraq, where many Syrians have taken up residence.

Less than 2,000 Syrian refugees have been accepted by the U.S. since 2012. Approximately half are children, roughly 25 percent are over 60 years old and another 2 percent are males of the designated “combat age.” But the Paris terror attacks, which have so far been blamed on European nationals, have reignited concern over whether continuing to admit Middle Eastern families poses a threat to U.S. national security.

A bipartisan vote in the House of Representatives last week authorized a bill that would require top national security officials to personally certify that each refugee from Iraq and Syria isn’t a security threat. FBI Director James Comey argued that the bill, as written, would prohibit the admission of any Syrian refugees. Yet the concern has been enough for prominent Democrats to split with President Obama’s plan to continue admitting refugees. Democrat Sen. Joe Manchin, of West Viginia, wrote a letter last week asking Obama not to admit any more refugees “unless federal authorities can guarantee with 100 assurance they are not connected” to ISIS.

“He wants to make sure we can certify people with 100 percent certainty,” said Jonathan Kott, spokesman for Manchin. “I don’t know whether we can do that now.” 

European nations require refugees to apply for asylum in the first country where they arrive. This rule is enforced with Eurodac, a European fingerprint database that was shared with international law enforcement starting in summer 2015.

It’s more difficult for Syrian refugees to find a new home in America because, along with additional screening from the U.S. Citizenship and Immigration Services, U.S. law defines “terrorism” more broadly than European law.

Define Terrorism

Under the USA Patriot Act, providing “material support” for terrorism is not only a means to deny refugee status, it’s punishable with prison time. The law makes it illegal to provide training, expert advice or assistance, service or personnel to groups designated at terrorist by the U.S. State Department. But it’s been criticized as an overly broad stipulation that could impose guilt by association against unintentional defendants (aid workers who provide food and medicine to Somalians, only for those supplies to wind up in the hands of al-Shabab, for example).

There are also three tiers of Terrorism-Related Inadmissibility Grounds that forbid those affected from crossing American borders. Tier I and Tier II apply to anyone involved in or connected with terrorist activity, but Tier III organizations are defined as “a group of two or more individuals, whether organized or not, which engages in, or has a subgroup that engages in” terrorist activity, including the attempted overthrow of a government.

“Tier III is a giant hole for refugees, because if any officer thinks someone fits into this quasi-definition of a group, they’re disqualified,” Micinski said. “We saw groups fighting against the Iraqi government fall under this category, even though they were fighting on our side. The U.S. State Department needed to create a waiver program to differentiate which groups don’t fit the terrorist definition.”

That process has become more intensive since the United States went to war in Afghanistan, and then Iraq. The Department of Defense integrated a database into the screening process in 2007 to include fingerprints, biometric and biographical information obtained from Iraqis who interacted with U.S. service members there. Another biographical check, this one from the U.S. Counterterrorism Center, was deployed in 2008, the Washington Post reported.

They also go through a medical screening test for diseases including tuberculosis. The process generally takes from 18 to 24 months from start to finish, and another security check waits at the airport from U.S. Customs and Border Protection officials.