It has always seemed to me that a great many Republicans firmly believe that no rational person could reject the policies they push, so the only rational answer to why so many people do reject them has to be voter fraud by their enemies.
Since those Republicans believe that everyone who opposes them is a liar and criminal, they also don't believe any of the evidence that anyone suggests proves that their policies don't and can't work. So like all "true believers" with an ideology to sell, they know it can't be the ideology that has failed. The problem has to be enemies opposing it and the fact that those supporting it haven't worked hard enough to get the ideology implemented proper over such obstruction.
There is also the fact that they know the mass population has no clue about the way they should be governed. They are just waiting to be led, either in the right or the wrong direction. In spite of their patriotic rhetoric, they have no belief in the ability of the voting public to get it right unless they are led. Democracy is only "magic" to them because it gives them a possibility of replacing the existing government themselves.
Dedicated Communists have exactly the same problem. They know in their hearts that Communism is the wave of the future, so if they just redouble their efforts it will be accepted. Needless to say, such doubled and redoubled efforts frequently involve criminal or near criminal activities, at least by some extremists.
The whole package is a coherent internally self-reinforcing meme, one that applies to true-believer ideologues. Everything they know to be true supports it, and their system of thought is designed to reject evidence that they might be wrong. My point, though, is that such people really believe what they are saying.