Fox News Channel chairman Roger Ailes may be the most consequential media and political figure that Americans don’t really know, says author Gabriel Sherman. A contributing editor to New York magazine, Sherman spent almost three years digging into Ailes’s journey from talk-show producer (“The Mike Douglas Show”), Broadway impresario and Republican political consultant to become the man who shaped the agenda-setting cable news network. In his book published Tuesday, “The Loudest Voice in the Room: How the Brilliant, Bombastic Roger Ailes Built Fox News and Divided a Country,” Sherman, 34, distills his voluminous research into a portrait of Ailes and his influence.

An edited Q&A with Sherman follows:

Why Roger Ailes? What attracted you to him?

Roger Ailes poses at Fox News in New York in 2006. (JIM COOPER/AP)

I’ve been covering media for a decade, and Fox is the biggest story on this beat, the most dominant cable news network. It generates $1 billion of profit for Rupert Murdoch’s media empire, and Ailes is at center of this subject. And yet a more nuanced and detailed portrait of who he is as a communicator and news executive and figure in the Republican Party is really unknown. He is the quintessential man behind the curtain.

What surprised you most about him?

He’s a master American storyteller. In that sense, what surprised me is that he fits into this amazing American tradition of hucksters and storytellers and mythologizers. That’s why I hope this book will elevate Ailes to the level of American characters. If you want to understand the second-half of 20th-century American history, Roger Ailes is one of the people you need to understand.

What, for instance, has he mythologized, either about himself or one of his candidates?

One of my favorite stories is actually Roger Ailes’s own creation myth. It’s the story of his encounter with Richard Nixon on the set of “The Mike Douglas Show” in Philadelphia in January of 1968. In Ailes’s telling, he talked his way onto the Nixon campaign. Ailes tells it that he had booked a belly dancer called Little Egypt on the show on the same day Richard Nixon was set to appear and, to avoid an awkward encounter in the green room, he stuck Nixon in an office so that he wouldn’t have to be with the exotic dancer, and that’s how Ailes stumbled into Nixon in his office, and they ended up talking, and Nixon said to Ailes,”It’s a shame a man has to use a gimmick like television to get elected.” And in Ailes’s telling, Ailes shot back, “Television is not a gimmick, and if you think that, you’ll lose again.” Now that’s an amazing story. But I went back, and I re-reported it. I went back to Ailes’ colleagues on “The Mike Douglas Show.” I look at the show logs [of the day in question]. And it turns out there was no belly dancer on show that day. It’s a wonderful story. But Ailes, as my reporting showed, wanted to meet Nixon, he sought Nixon out and was intensely interested in working on the campaign. What it reveals is that Ailes downplays his ambition while amassing power.

For years, people have said that Fox News was closely tied to the Republican Party. You suggested that Fox is bigger than the GOP. How do you mean that?

Fox has surpassed the GOP. Fox speaks to a phenomenally large bloc of committed conservative and Republican voters. If you look at the 2012 election, Ailes took it upon himself to run Mitt Romney’s media strategy. He said, in meetings with his executives, that he didn’t think Romney had the spine to go after Obama, in Ailes’s words, “to rip Obama’s face off.” He said, “We’re going to have to do a lot to get this guy elected.” And he did that by aiming Fox’s firepower at the president and building him up as a socialist, as someone hostile to capitalism, [perpetrating] a government takeover of health care, you can just go down the line. And that image of Obama and Romney, as branded by this very populist and extreme version of the Republican Party, stuck in the minds of voters.

Your subtitle says he “divided a country.” Weren’t we pretty divided before Roger Ailes?

What Ailes did more effectively than anyone of his generation is that he was able to sustain the divisions that cleaved the country throughout the upheavals of the 1960s. Ailes sustained Nixon’s Silent Majority coalition of mainly white, middle-class, conservative voters, fiscal conservatives, social conservatives, hawkish on foreign policy. That voting bloc helped Richard Nixon get elected in 1968 and ’72. It was ultimately the Reagan Democrats who were the same voters that turned out for George H.W. Bush in 1988 when Ailes hammered Michael Dukakis as soft on crime and weak on foreign policy. That coalition is the coalition that Ailes, through his use of wedge issues on class, patriotism and religion, was able to sustain far longer than perhaps would have been possible if there had not been such a genius political communicator. What Ailes did is that he surfaced all of those resentments and tensions in the culture that keep a reliable voting bloc intact over four decades.

You’ve suggested that Ailes controls the American news agenda? Really?

Ailes’s power is such that whether you watch Fox or not, Roger Ailes is speaking to you every day because the way he frames the headlines is so powerful that the rest of the media is forced to respond . . . The most important example is MSNBC’s decision to tack left to appeal to a progressive audience. The fact that Ailes fractured the cable news landscape into ideological segments is just one part of it. But beyond the partisanship, Fox [exerts] a gravitational field that affects everyone. I’ll give you just one example: the war in Iraq. I interviewed officials in the George W. Bush White House who told me that Fox’s cheerleading of the war effectively silenced the isolationist wing of the Republican Party, that it was a major factor in quieting voices on the right that were cautious about a rush to war in Iraq, voices like Brent Scowcroft and Pat Buchanan, because those voices were not being heard on Fox.

What does Rupert Murdoch think about what Roger Ailes has done with Fox News?

The book traces the evolution of Murdoch and Ailes’s relationship, which is a complicated and fascinating one. What Rupert Murdoch wants are two things: Number one and foremost, profits, and number two, influence. But Ailes and Murdoch have different worldviews. Murdoch is a pragmatist first and a conservative second. Ailes is and has always been a conservative. Ailes has pushed his politics far beyond where Murdoch is, especially in education, immigration and climate change. Ailes is in a position where Murdoch and him may disagree on issues, but Murdoch relies on [Fox’s] profits, so Ailes has complete independence to program Fox as he sees fit even if there are issues on the network that Murdoch disagrees with.