No, you discuss your disagreement with your superior and come to an understanding. You don't do an end around by blind siding him by sharing that disagreement in public.
Well, I don’t think it is that clear cut.
In certain situations, yes, but in general, I don’t believe you need to come to an understanding of some kind as long as the goals and actions of your superiors don’t conflict with your own fundamental principles or beliefs.
If they do, you either have to come to an understanding as you said, or you have to leave.
One of my goals is to NEVER surprise or allow a superior to be surprised by something I had any hand in. This guy surprised his prospective boss, and Trump was right to nip it in the bud.