bernardino shooting. >> donald j. trump is calling for a total and complete shutdown of muslims entering the united states until our country's representatives can figure out what the hell is going on. >> now since then, it's important to point out trump has described this plan in several different ways, but neverly formerly rolled back the temporary muslim ban. saying he's calling for an expansion. >> i actually don't think it's effective. in fact, it's an expansion. i'm looking now at territories, people were used the word muslim, oh, you can't use the word muslim. remember this, and i'm okay because i'm talking territory instead of muslim. >> a new legal unit investigation gives us the first comprehensive policy analysis of exactly how this policy would actually be administrated. and as chief legal correspondent arie melburn breaks it down. >> our legal unit spoke to burdener security and homeland security experts in both parties