I think perhaps the only thing that might work is some form of Socratic questioning. You cannot convince someone that they are wrong, they have to convince themselves. All you can to is to try to get them explain, in detail, their beliefs and the basis they have for holding them. If their beliefs are logically, morally and rationally consistent, you will not change them. But if they hold flawed beliefs (which we all do to varying extents), then sincerely questioning them from the very foundation of what we mean by all of the terms used will expose the logical fallacies in those beliefs. The person then has a choice to either come to terms with their mistaken belief and change it, or to delve deeper into their fallacious belief. But, by having them devise the argument against their own beliefs, the likelihood of them doubling down is greatly diminished. If you try to just force it and explain to them how they are wrong, they will almost certainly double down. This is not something that will be done in a single sitting, or by a single person, but it can be done piecemeal by many people over an extended period. When people start telling you something stupid, you can use Socratic questioning to get them to delve into what they actually mean and what their basis for holding that belief it. Feign ignorance if necessary, get them to explain it, but you must be ready to gently point out the contradictions, otherwise they may only convince themselves further. The key is to plant a seed of doubt in their minds. If done effectively, this will linger and possibly grow. They won't change their mind straight away, but this seed of doubt will trigger when they encounter certain situations. This seems to be the primary way that most "former liberals" are made. They were all in on it, but something that planted a seed of doubt in their minds, then as time went on they started to see the world from a slightly different perspective. Gradually, the liberal ideological positions that they formerly would have strongly held no longer resonate.