Associate Professor Jennifer Mercieca said Mr Trump was using paralipsis to get people on his side while also avoiding accountability.
"It's a great way of entertaining a crowd, making them feel like they're important and smart ... polarising them from somebody else," the Texas A&M University academic told the ABC.
Prof Mercieca is an historian of American politician rhetoric, which is essentially the art of persuasive communication.
As an example, she pointed to Mr Trump's criticism of former Fox presenter Megyn Kelly, who infamously questioned the then-Republican candidate about his offensive comments on women during the first Republican debate.
Mr Trump tweeted later: "I refuse to call Megyn Kelly a bimbo, because that would not be politically correct. Instead I will only call her a lightweight reporter!"
"He's attacked her, polarising the audience by making her an object of hatred and at the same time it's funny," Professor Mercieca said.
She said the tweet also made people feel like they knew something about what he was really thinking.
"(They) feel like they're important and smart and on the inside."
Importantly, Mr Trump is also able to avoid criticism because he can deny he said she was a bimbo.
Using this technique he has also been able to deflect criticism for things like retweeting a white supremacist or a quote from dictator Benito Mussolini.
Prof Mercieca said it was something that a stand-up comedian often did in telling jokes, and which allowed Mr Trump's audience to identify with him.
She is now identifying Mr Trump as the "new spectacular demagogue" for his use of spectacle, marketing and public relations techniques, and his use of social media to go around traditional news media and speak directly to his supporters.
A demagogue, or rabblerouser, is a political leader who appeals to popular desires and prejudices to attract support, rather than using rational arguments.
Professor Mercieca predicted social media would encourage the rise of a demagogue and Mr Trump proved the point.
"Social media has provided a platform and a method of reaching audiences that prior presidents did not have," she said.
"He's all about making it entertaining for people so there's this bizarre thing where you can't not look, you have to pay attention to him, he's so good at getting attention while at the same time he's saying some really terrible things that have a lot of impact."
One of the problems with being a demagogue, is that they can refuse to accept responsibility for their actions.
"(Mr Trump) can shrug and claim that he's simply giving voice to an idea," Prof Mercieca noted in an article on The Conversation.
When asked about Mr Trump's war on "fake news", which has prompted some to note "that's how dictators get started", Professor Mercieca was more optimistic.
She said the President just seemed to be constructing an enemy to use as a foil, rather than seriously cutting back press freedoms.
"He knows that with his audience and his demographic in particular, the press isn't very popular so he's able to use them as an enemy that he's constructed," she said.
"I don't see him actually trying to create policies or prevent the press from having a role in the government or anything like that.
"It's part of the spectacle of his presidency, he's created this opposition, this enemy character to go along with his president character that he's developed."
