The Loudest Voice in the Room: How the Brilliant, Bombastic Roger Ailes Built Fox News—and Divided a Country by Gabriel Sherman Random House, 538 pp., $28.00

President Obama thumped Mitt Romney in the 2012 election by excelling with the voters who are most likely to influence future American elections. Obama won 55 percent of votes by women, who go to the polls in larger numbers than men. The president attracted 71 percent of Hispanic voters and 73 percent of Asians, groups that are growing as a share of the population. Among voters under thirty, Obama won 60 percent. Romney, on the other hand, did very well with older white men. The 2012 race looked winnable for Romney at times because of persistent high joblessness. Yet not only did he lose, he delivered to the Republican Party a bleak forecast of its prospects.

A month after Election Day, Republican National Committee Chairman Reince Priebus commissioned a report about what had gone wrong. The study’s authors did not cite Fox News by name, but they made clear that they thought the network’s polemical programming aimed at the Republican base was a major part of the problem. “The Republican Party needs to stop talking to itself,” they wrote. “We have become expert in how to provide ideological reinforcement to like-minded people, but devastatingly we have lost the ability to be persuasive with, or welcoming to, those who do not agree with us.”

Since its creation in 1996, as an arm of Rupert Murdoch’s media empire, News Corporation, Fox News has made a killing by providing ideological reinforcement to like-minded conservatives. Although the audience for Fox News is aging and leveling off in size, it remains the largest of any cable news network in America by far. The network’s profits in 2012 were just under $1 billion, according to the Pew Research Center. Its profit margin has been above 50 percent in recent years, a rate almost unheard of in mainstream business. Fox’s success has been due in no small part to the insights of Roger Ailes, a former Republican media and campaign consultant and the network’s first and only president, who is the subject of the journalist Gabriel Sherman’s thoroughly reported biography, The Loudest Voice in the Room.

Particularly during the George W. Bush administration, Democrats loathed Ailes because they feared he had devised a propaganda-inspired communications strategy at Fox News that might assure long-term Republican hegemony. There was some basis for this anxiety. By Sherman’s telling, for example, Ailes had a significant and self-conscious part in publicizing the “Swift Boat” smear ad against then Senator John Kerry during the late stages of the 2004 presidential campaign, an ad that purported (through falsehoods) to challenge the senator’s account of his wartime service in Vietnam. More recently, however, following two consecutive presidential defeats, at least some Republican elders have apparently come to view Ailes as a kind of Frankenstein monster that must be subdued and…