I assume you are referring to something like defamation but controlled by the state
Maybe do issue follow ups, so if someone says something and later it is contested prioritise the contestants until they get similar reach. For example, if a politician says he never met with someone and a photo of them together is revealed make sure that their claim is displayed together with the new photo.
Things like this.
That's what fact-checking is. It's widely heckled.
However, some sort of "fair & balanced" law would have to enforce this.
Edit: and to respond to sibling comment about fact-checking being heckled...
The mechanism here would have to somehow force a similar amount of views. For example, if a lie gets 1MM views, then the proof of the lie should have to gain 1MM views before the original author can gain leverage of the algorithm again.
Of course the new system will eventually be abused, however, it's a step in the right direction. And when that eventually fails to be recognizable, another set of checks and balances must be layered on top.
