Good point, but people also need to understand the explanation, and they have to believe the change of mind is genuine and that x, y, and z are the genuine reas

Good point, but people also need to understand the explanation, and they have to believe the change of mind is genuine and that x, y, and z are the genuine reasons (as opposed to some other contingent or craven reason) for the switch. For example, John Kerry's "for it before I was against it" sounded to some like he was dissembling and hiding that he may have changed his opinion on an appropriations bill simply because the wars were becoming less popular with the public.