Katie Pellico, CNN Business

New York Times chief television critic James Poniewozik asserts that Donald Trump's evolution as a "TV character" was a critical aspect of his ascent to the presidency.

In his new book, "Audience of One: Donald Trump, Television and the Fracturing of America," Poniewozik also examines Trump's TV obsession and how it has affected his time in the White House.

"He in very many ways used television to become president, but then TV kind of became the president, because what he was seeing on TV set his agenda and controlled his mood and determined the world that the rest of us would live in," Poniewozik told Brian Stelter on this week's "Reliable Sources" podcast.

Trump's recent fixation with the coverage of his false claims about Hurricane Dorian and Alabama are just the latest example of this Trump-TV feedback loop.

There were, of course, many factors that helped Trump win the 2016 election. But Poniewozik's book describes how the power of television was a pivotal factor. It wasn't always the case "that you could go pretty much directly from hosting a reality game show in primetime on NBC to becoming the most powerful person in the world," he said. That happened in 2016 "because of TV. It happened through TV."

Here are five takeaways from the podcast conversation:

-- Trump's arc as a TV character "evolved in stages": From "braggadocious New York character" and "abrasive" author of the "Art of the Deal," to the "self-parodic sitcom character" of "The Apprentice," to "the world of cable news," Poniewozik said Trump reflected and adapted to "the kinds of different television" that he saw at the time.

-- TV's changes benefited Trump: Poniewozik's book makes the case that the Trump presidency was made possible through changes in the TV business, including a shift from broadcast to niche programming. "TV went from a sort of three-network mass medium where you were trying to reach a broad audience and be broadly palatable, to a fragmented niche medium where it was about building intense audiences," he said on the podcast. Trump similarly built an intense audience through his rallies and TV interviews, where he could win fans by being an "abrasive, polarizing figure."

-- Fox played a key role: With the help of NBC, Trump created an exaggerated image of himself as a billionaire businessman on "The Apprentice." But his appearances on Fox were also crucial. Trump's recurring segment on "Fox and Friends," starting in 2011, "transitioned him from entertainment figure to political figure," Poniewozik said.

-- Trump as the antihero: "Audience of One" details how the TV antihero emerged "in part because TV was more fragmented." For Poniewozik, figures like Tony Soprano, Walter White of "Breaking Bad," and even Richard Hatch, the winner of season one of "Survivor," were possible because producers were "pitching to smaller audiences," and with that, "you can create these things that are not necessarily for everyone." Poniewozik said it was "this idea of rooting for the bad guy" in popular culture that helped to pave the way for Trump's TV persona and presidential run.

-- There are numerous ways for politicians to use TV effectively: Barack Obama also "used media to sort of present himself as a symbol and used that to weave together a political message that was kind of larger, and that people could bring what they wanted to," Poniewozik said. "If you aspire to be any kind of political leader of any party," he said, then you need to recognize how people communicate. "You can like it or you can not like it, but if you don't engage on that field -- and in some way make yourself the protagonist -- somebody else is going to claim the spotlight."