(CNN)John Dickerson spends a lot time thinking about politicians -- as host of CBS's "Face the Nation" and now as the author of the new book "Whistlestop: My Favorite Stories from Presidential Campaign History," a collection of presidential campaign lore.
John Dickerson: Hillary Clinton 'not a very good campaigner'
The Axe Files, featuring David Axelrod, is a podcast distributed by CNN and produced at the University of Chicago Institute of Politics. The author works at the institute.
So when asked to size up Democratic and Republican candidates Hillary Clinton and Donald Trump as they move into the general election, Dickerson considered the way both candidates perform under the grueling demands of a national campaign.
Clinton's challenge, Dickerson suggested, is that her skills and persona may lend themselves more to governance than campaigning.
"Campaigns maybe encourage us to pay attention to attributes that maybe aren't that important in the presidency," Dickerson said in a conversation with David Axelrod on "The Axe Files," a podcast produced by CNN and the University of Chicago Institute of Politics. "There are some [attributes] that are, of course, crucial. I think she's just not a very good campaigner."
"Once I asked her to give us three words that give us a sense of who you really are," Dickerson recalled. "She kind of threw up her arms and said, 'I am a real person!' I think that was a genuine expression of frustration with the process. It was a genuine response."
Trump, on the other hand, is much more open and accessible but often unwilling to acknowledge his own statements or back up his claims.
"The challenge with Donald Trump is that he'll deny things he said the day before or even in the same interview," Dickerson noted. "And then sometimes when you try and talk about a fact that he misstated or something that he said out loud that he now disagrees with himself on, it's very frustrating. On the other hand ... he's quite candid on some things in a way that I can't imagine any other politician being."
Dickerson also points out that Trump's unconventional, carnival style may seem entirely new, but has roots in the American political history he charts in "Whistlestop," which will be released Tuesday. It is based on Dickerson's podcast of the same name.
"In 1840, William Henry Harrison is the first one to really campaign as a candidate and the campaigns were totally frivolous, I mean, people were drinking hard cider all day. They were big parades, no one was debating the issues," Dickerson said. "So when you see Trump flying his plane over the stadium where he's going to give a rousing speech, it feels very much in touch with that."
During the hour-long conversation with Axelrod, Dickerson also likened Trump's run to former (and future) Alabama Gov. George Wallace's third-party effort in 1968.
"People thought '[Wallace] is not going to get on the ballot' and he got on the ballot in all 50 states. People thought 'Oh well, it's just a regional thing,' but he started to do so well in the North that both Humphrey and Nixon were worried about Wallace because there were a lot of working class whites who resented the riots, peace marches, as well as the African-American rising labor costs."
The difference, Dickerson says, is that Republicans today are "speaking out against Trump in way no one spoke out about Wallace."