Singling people out based on religion (as is being done with refugees) is certainly a violation of the constitution.  

If this was for national security, then why only Muslims?  Look at the history of attacks in the North America...they were caused by Christians, Muslims, Sikhs, etc.  Why not ban them all then?

This is a media stunt by Trump to placate the mass population who don't understand the first thing about Islam or the Middle East, and based on the ignorant comments here, it seems to be working.