I don't want to appear patronising, but in economics there's a term known as 'perfect information' - when the consumer knows everything he needs to make the best decision. So if he goes to a garage to buy a car, and knows everything about the vehicle's condition, he'll pay based on that information. But naturally, there's like to be a salesman there who'll try to exaggerate its worth in order to get him to pay more, and pressure the customer, to make him believe someone else is interested in a car that's taken his fancy.
In a democracy, the salesman is the media. It's the media that disseminates the information upon which the electorate (or the consumer, in the above analogy) depends when he makes his choice. The media might lie about the state of the economy, immigration. It might lie about big things, like an imminent ecological threat to the planet, or a terrorist attack, or some other historical event in order to distort the electorate's perception of the world.
In a democracy, whoever controls the media controls the narrative and determines the election. This is why the internet is such a threat, and why net censorship is so important. A democracy cannot function when the electorate depends on information controlled by a few oligarchs.
