Convincing someone that they’re wrong about a political belief, which may as well be a religious one at this point, is a whole different matter.
In my experience, that's absolutely impossible. However, what is indeed possible is to show someone that what he supports is *in contradiction* with what he really wants. A lot of people deep down (very deep down) want and specially need similar things, but they react to it differently and often end up getting caught on opposite ideological frameworks and apparently wanting different things. Well yes, they end up advocating for the opposite concrete and specific actions (or policies or whatever), but it's likely that there's no meaningful difference under that (very thick and messy) ideological cover.
With this in mind, I have changed how a handful of people think. It must be said that they were/are close to me and I saw clearly (at least from my perspective) that there was an actual contradiction between their deep down values and their professed ideology (which was different between them), that may not always be the case. What I know for sure is that if I had talked to them in terms of criticism to their ideologies per se (instead of in relation to their deep values and wants), I would have just made their ideology stronger.
Right, but the amount of work you describe sort of supports my point, or at least the fact that these were people who were already close. I was more referring to everyone else =)