I know it's been a long time since I wore a uniform, but I seem to remember that the President (even one who did not deserve the office) was not required to return a salute from someone in uniform. In fact, as I recall, it was improper for him (or her) to return a salute. He may be Commander in Chief, but he is not in the military. Don't misunderstand, I am not defending him, just stating a fact.
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