Cut off the nose to spit the face, eh? That's a logical approach....
Ever hear of background checks? Passports? Government ID? Interpol? Home country databases? Traveling from a Muslim country? Like Pakistan, Afghanistan, Iran, Iraq, Saudi Arabia, North Africa etc. Boom. Goodbye. See ya later bud.
I think what you're forgetting is America doesn't owe anybody shit. America can let in whoever they want. Foreigners have NO RIGHT to enter the United States. Muslims, or whoever else. The UNited States dictates ITS OWN immigration policy. Not some camel-fucking towelheads halfway across the world.
Statistically, Muslims don't hold the same values WEstern Democracies do. So it makes sense in the general, to curb their immigration.
So you would cut off all student visas, all business visas, all transportation of Muslims to the U.S. -- even for Muslims from places like Kosovo who are very supportive of the U.S.
There are global business ties and interdependence across the earth. Do you have any idea how many white Christian Americans are working in the U.A.E., Dubai, etc.? Do you actually think that Muslim countries across the globe would not retaliate and ban U.S citizens from their countries?
Do you actually expect Muslim countries to continue provide background information on Visa applicants after Trump's ban is implemented? How would you even get the cooperation to find out if a traveler is Muslim or Christian? Well... the foreign government will not tell you anymore.
Trump's proposal is unworkable and mindlessly discriminatory. There is a big difference between performing better screening and banning people of a particular religion.