The Final Presidential Debate: Five Kinds of Evidence
October 25, 2016 by Bill Rosenthal

The Final Presidential Debate: Five Kinds of Evidence

Historic though they might have been, the second and third presidential debates were surprisingly unpersuasive. If Hillary Clinton is leading Donald Trump in the polls, it is probably less due to her persuasiveness than to his recurring and deepening scandals. But I’m not here to write about politics. I want to look at the quality of the communication in the third debate — specifically, how the candidates handled evidence. Any quotations I use are from the transcript posted by the website Politico.

Neither of the candidates is a particularly inspiring speaker. Donald Trump is often incoherent in his storytelling and sentence structure, and he doesn’t project his voice well. Hillary Clinton doesn’t project well, either, and the serenity she employs to confront her opponent precludes some of the passion needed to persuade.

The two candidates differ dramatically in the way they use evidence. There are five kinds of persuasive evidence.

1. Data. Data are statistics and facts. Hillary Clinton cites court rulings, statistics, obscure geography, and history with ease. Whenever she wants to make a point, she has hard data to back it up. Donald Trump has little data at his command, and usually substitutes assertions: “So my plan, we’re going to negotiate trade deals. We’re going to have a lot of free trade. More free trade than we have right now.”

Check out more political blog posts

2. Expertise. This is the opinion of someone your audience will accept as an authority on the subject. Hillary Clinton used expertise when she said that 17 intelligence agencies have confirmed the Russians are trying to influence the American election. Donald Trump’s use of expertise is rather ham-fisted, as when he said, “I have 200 generals and admirals, 21 endorsing me. 21 congressional medal of honor recipients.”

3. Cases. Cases make an argument real. Hillary Clinton used a case when she said, “I was thinking about a young girl I met here in Las Vegas, Carla who is very worried that her parents might be deported because she was born in this country but they were not.” Lack of cases may be the biggest single reason that Donald Trump has not attracted any new supporters in the course of these debates. He doesn’t use individuals to make any of his arguments real. He just repeats his talking points.

4. Story. This is something from the speaker’s personal experience. It’s another form of evidence at which Hillary Clinton is a master, as when she characterized her 30 years of experience in public life, comparing it, decade by decade, with Donald Trump’s business misadventures and celebrated gaffes. Donald Trump almost never cites parts of his own personal story in any meaningful way, offering only generalities like, “I built a massive company, a great company, some of the greatest assets anywhere in the world worth many, many billions of dollars.”

5. Image. This is a way of cultivating emotion by creating a picture. This is the one area in which Hillary Clinton comes up short against Donald Trump. In their discussion of abortion, Donald Trump said, “If you go with what Hillary is saying, in the ninth month you can take baby and rip the baby out of the womb of the mother just prior to the birth of the baby.” Whether or not this is how an abortion ever happens, you have to agree it’s a powerful and emotional image. Hillary Clinton never created an image in the course of the third debate, much less one so powerful.

There were interesting moments related to evidence in the third debate, but in general, the quality of the communication in this debate was such that I’m glad the debates are over.