The only way to remove manipulation is to remove emotion from politics. So you either need someone who knows what needs to be done and can't be influenced otherwise, or a system that is not easy to influence, like one based on facts and evidence.
Enlightened dictator is a high risk high reward type of deal though, even if he is awesome then there are no guarantees afterwards. Basically rolling dice. Of course you need to do other things too, like restricting the influence of money in politics, but even with decent politicians the masses are vulnerable to manipulation by various interests. That really is the Achilles heel of democracy. So the system needs to be transparent and based on the scientific method. It really is the only way to remain impartial and objective.
We have a long way to get there however, so I think a short term solution is to invest in education. I know it's kind of a platitude and also imperfect, but history and research has shown that education really is the defining factor between the good and the bad. A democracy needs an educated populace, monarchy was fine and natural for certain times because it pretty much the only thing that could have worked when 95% of the populace was illiterate and relatively stupid. Sudden democracy in the Middle Ages would have been a disaster. Unfortunately there seems to be a trend of anti-intellectualism recently is certain places like the UK and US. Make no mistake, whether it is deliberate or not, it is exactly what many interests want. Dumb people are much easier to manipulate.
I don't think that's the only way. At least, I think there's a few things to try first.
If information dissemination is being exploited due to new technology, first we should try to fix that in various ways. There are various other problems that might or might not have full or partial solutions as well.
When you have a hole in the henhouse that lets a fox in, the first step is to try to close the hole and possibly trap or kill the fox, not to stop raising chickens. Even if new holes are occasionally dug, as long as it's still worth it to grow chickens, you don't just give up.
There will always be ways to exploit various systems, you can only react, not prevent in those cases. Because of entropy, complexity is always increasing. It means that not only are the problems going to be getting harder to address individually but that new problems and systems will be created at an exponentially increasing rate. Those problems are superficial in nature and more like symptoms in any case, than real causes. You have to address the root of the problem and that is human nature. Instead of chopping of the heads of a hydra, shoot in in the heart or something.
As long as politics can play on emotions, people will be liable to act irrationally and thereby manipulated.
I personally think the solution may be to remove the idea of representation from government, because the perverse incentives for anyone at a structural node are tempting and human nature is fragile. You can try to engineer corruption and rent-seeking with rule systems, but as we've seen in many Communist countries taking money out of things doesn't necessarily get your a more equitable or sustainable society.
I see a future with a much abridged legal code that is maintained somewhat like Wikipedia or a version control system, and whose implementation is built around blockchain technology and a narrowly-defined ethical calculus. However I can only handwave this for the time being as the challenges of computation legal and governmental systems are non-trivia, not to mention offering the many novel problems that would surely ensue.
I'm not sure what to do about giving the vote to people; arguably democracy is very good, but I would rather have per-commune direct democracy (with instantly recallable delegates or without) rather than a representative democracy.
In short, I want to do away with voting for masters, as it will be unjustified authority no matter which way it's taken.
Edit: can people please explain why they are downvoting? It would be nice to know so I can improve the quality of my posts in future.
You believe in an oxymoron?
In Marxist Communism (and, with variations that are important but not relevant to this discussion, it's derivatives through Leninism), "Communism" is the desired stateless end-state, and the "dictatorship of the proletariat" in which the workers seize control of the means of production through the State—Socialism—is a transitional stage used to get from Capitalism to Communism.
Non-Marxist Communism seeks the same stateless end goal by other means; Anarcho-Communism is, in a sense, among the purest forms of Communism, since it seeks fairly direct (not necessarily immediate, but constsntly in the same direction and not the out-and-back "empower the State to destroy the State" approach) transition to the statelessend end-state.
Consider something else, reproduction. While not all people want to have children, it is a major desire of many people. How do we ensure equal opportunity of reproduction to all who wish to have children?
I do not think that Socialism itself does away with the problems of humanity, but it does away with the power relationship between proletarian and bourgeois, and also all those other historical classes.
Communism isn't about equality of outcomes, it's about having the ability to apply your labour in the way which you are able to, in order to provide for yourself. Of course we must work to live (which is unfortunate, but Socialism helps mitigate that by voluntary means). It is totally fine, in my opinion, to have more than the other person next door. In a Communist society, the only reason why you would have more is because you worked harder, put more hours in, or were more efficient at what you do than the other person.
With regard to children, I don't know how to answer that question, and I don't know if there exists such a way by voluntary association which leads to such an outcome as perfect equal opportunity for reproduction. I would be very interested in finding a way, though.
Karl Marx died in 1883 so while he was probably able to make guesses about how steam engines would be deployed in the future he never lived to see an actual automobile. Adam Smith's economic insights were likewise somewhat limited by the technology of his day; one has to be careful not to attribute knowledge that we only enjoy with hindsight to economic theorists of earlier eras.
This statement is true in the same way 'Anarcho-Communist' is. Care to guess how?