>>Either do it correctly or don't do it at all.
Actually I agree with you.
My pick is that both Bush and Obama were deep in thought and saw the marine and actually wanted to show respect- but goofed doing it with something inappropriate in hand. Maybe an aide could temporarily collect the coffee cup or mutt when the boss is approaching a marine who is going to salute? Or many presidents actually have 2 hands...
FWIW- if respect matters, then it ought to be a 2-way street without regard to the individual wearing the uniform or holding the office, should it not? IOW this should have nothing to do with whether people like or dislike the particular soldier or the dude with the cup.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1