"Many cases recognize that the government must have some discretion as to the choice of art it puts on the walls of its offices, even where the government is acting as an arts patron."

The First Circuit has affirmed the District Court's decision that it was not a First Amendment violation for the Governor of Maine to remove a mural from a state office.  The decision is here.  News story here.  Background here.

Eugene Volokh:  "Sounds right to me .... When the government puts up a particular item of speech (art, text, video, or what have you), not as part of an open-to-a-diversity-of-speakers public forum but instead because it likes that particular speech, it should later be free to take it down, even if only because the new administration now dislikes the speech, finds it inappropriate in this location, finds it too controversial, or what have you."