Presenting one position without pretending to agree

If you land on a single position, present it as a joint one and let the person who disagreed say so once, plainly and calmly: I would have chosen differently, and I am behind this. That is honest, and it is a good thing for a young person to watch, because it models disagreeing without withdrawing.

What does the damage is the private undermining afterwards — the quiet comment in the car, the raised eyebrow. It teaches the child that the decision is still open and that one of you can be played against the other. If you have agreed something, hold it in public and take the rest back to each other.