Steve Syria reminds me of Coventry, England after the bombing raid of November, 1940. The Registry of Births, Deaths and Marriages was burned to the ground and all records lost. You can imagine what it was like when someone needed a birth certificate, death certificate, marriage certificate, etc. For decades afterwards, criminals used false birth certificates from Coventry prior to November 1940. They had to be accepted at face value. No one could get an official verification. The same situation exists in Syria today. Even with the 18-month plus vetting, there is no guarantee that the person or persons admitted are who they say they are. Yes you can finger print people, use facial recognition, do DNA tests, and check Social media and Google. But it's not a perfect system.