I'm not sure people are
really fooled by lies that much, rather they see them for what they are, a tool to persuade for something they emotionally connect to.
It's easy to despair at the apparent lack of rationality of my fellow human beings and their ability to be manipulated at the emotional level by people who don't have their interests at heart.
However aren't people who aren't emotionally controllable the definition of
psychopaths?
So perhaps rather than focus on pointing of the lies and demanding a fact based debate, we should embrace the emotional and simple label people as liars and have the courage to talk about the real emotional issues.
Take - 'Build the wall' - clearly a not a great practical solution - but to treat it as such is to misunderstand that's it's a simplified slogan that covers a large raft of underlying issues - worries about immigrant, job security, crime, drugs, culture, racism etc.
In fact by criticizing the wall as a practical solution you are implicitly agreeing with the underlying agenda - that there is a solution needed. If you do indeed agree with the underlying agenda and only disagree on the solution then you need your own slogan 'Dig a trench' or 'Shoot on sight' , if you don't then you need something like 'Welcome in', 'Together we are stronger' etc.
In the UK - arguing 'Get Brexit Done' is silly as it's just the start of a long set of negotiations. However if you focus on that - you are effectively again implicitly agreeing that it needs to be done, just arguing on a technicality.