Facts are pesky little things to Trump and you.

Vetting begins with the U.N. High Commisioner for Refugee, which determines who counts as a refugee, who should be resettled (about 1 percent) and which countries take them. This alone can take 4 to 10 months.

If the UNHCR refers refugees to the U.S., they then face scrutiny from federal intelligence and security agency officers.

1)Their names, biographical info and fingerprints are run through federal terrorism and criminal databases. 
2) Meanwhile, the refugees are interviewed by Department of Homeland Security officials.
3) If approved they then go through a medical screening, a match with sponsor agencies, culture orientation classes and then, one more security clearance.
4) Syrian refugees must also clear one more additional hurdle. Ther documents are placed under extra scrutiny and are cross referenced with classified AND unclassified information.