I lived in the era where we were to fear the ever present Communist threat. Best to check under the bed nightly to see if one of them was hidden there. They were our greatest threat....really?
Today the new fear mongers are promoting fear of Muslim and American ones at that. 
A check of our mass murderers of late would show that those in the minority of the list are Muslim. We have cultivated our own disaffected youth, many with a Christian background who think mass murder of their countrymen is the thing to do.
If you are looking for something to truly fear.....your chance of being killed is greater from those who text and drive than those who seek safe harbor from war in our land. Time to check stats and get real.