Trump uses the same rhetoric and propaganda style as George W. Bush, however taken to a new extreme. His faux pas, and "Plain Folk" style are precisely the appeal. If someone sounded intelligent and reasoned, it would not appeal to the same crowd. He is not a lone outsider fighting against the system, but using an established propaganda tactic that is proven effective and appeals to his voting base. The next candidate that wishes to appeal to this base will need to learn this same approach. Stupid got him elected.
This is an interesting article analyzing Bush Jr. rhetoric and propaganda style. The main points I will include here:
(PDF) The Language of Propaganda in President Bush Jr. Political Speech
1. Name calling: words like "socialist", "terrorist", "thug", etc.
2. Glittering Generalities: "It is used to connect someone or group to beneficence images or enhances people's position in order to have a comparative statement between goodness and meanness". This is often combined with name calling, so exaggerate an "us vs. them", "for us or against us" mindset.
3. Transfer: "This technique is actually used by the speaker in making some motions that have a great sound; full of something well-respected to draw out enthusiasm from the audiences, even more, including some religious sounds." This can include prayers and "God blessing".
4. Testimonial: "This technique is to take someone who the audiences “know†even “likeâ€, and attempt to transfer the famous peoples‟ opinion to the audiences. In other words, the user of this technique is to transfer a favorable image of an individual person to the aims of the speaker."
5. Plain Folk: "One strategy in propaganda is an attempt to convince the audience that a famous person and his ideas are one of the participants. It is almost similar to the previous technique, but it is more specified. It is not only talking about the individual job but also the ideological foundation of the speaker itself. It seems like exploiting the speaker‟s position and making a special appeal that the speaker is one of the audiences."
6. Bandwagon: "The making of an appeal that “you are not alone†or “everyone else is doing it, so should you"."
7. Fear: speaks for itself.