The Obama administration plans on bringing in 10,000 Syrian refugees this year.
Because of the attacks in Brussels, France, along with the mass rapes in Cologne, Germany, and Sweden's no-go zones for law enforcement which helped to harbor these individuals, we cannot let any of these people in as we do not know who they are, what they want, or even if they are affiliated with terrorist groups because of the conflict in Syria.
Along with this, the United States MUST take care of its own people first before deciding to open its doors to people from these war-torn countries.
Sources;
http://www.bbc.com/news/world-europe-35231046
https://swedenreport.org/2015/05/18/police-yes-there-are-no-go-zones-in-...
(Cannot fit rest of sources here)