But the nipickers of Trump’s plan will claim that muslim refugees could pretend to be Christian.
Some undoubtedly would, but there are screening techniques, such as monitoring for eye dialation with high-def cameras in response to certain stimuli. Cheap, quick, and easy to train screeners.
And if they are caught being practicing muslims later, then the government ‘owns’ them and might use them as double agents.
I would think also that Christians would have churches with records to back them up in most cases.