If you cannot honor the man, then honor the office. If you cannot honor the office, then one more patriotic bond has been severed.
The office of the president has meaning and importance that transcend the views of its current occupant. Though elected by a part of America, the president becomes a symbol of its whole. The respect we accord him does not imply agreement or endorsement. It reflects our appreciation for constitutional processes. So a presidential visit is always an honor. The televised arrival of Air Force One, the motorcade, the playing of "Hail to the Chief," the audience standing as the president enters -- all these express a proper respect for presidential legitimacy.