Do you think a judge will accept a “all I know is that he is Muslim” argument as probable cause that the Muslim guy will go on a shooting spree?
That is a good legal question, because the law is ambiguous. What would help him a lot is if he had a legal phrase he could use, that is unspecific. In effect he has to use the ambiguity of the law by himself being ambiguous.
“Did you refuse to sell to him because he was a Muslim?”
“Oh, no, your honor. I suspected that based on his appearance and behavior, that his purchase of the gun was being made for prohibited reasons. Based on the law which says I can be held accountable for selling a gun to a person trying to buy a gun for prohibited reasons, based on their appearance and behavior. So therefore I could not legally sell him a gun.”
Importantly, the law does *not* reward either honesty, veracity, or clarity in testimony. What it does reward are pat statements that cannot be cross examined or refuted.
No matter how a judge or prosecutor might rephrase the same question to him, he must give the same pat answer. This is done so much by the police that they give testimony almost ritualistically, as it causes the least fuss.