A few days before the presidential election last November, Roger Ailes, the chief executive of Fox News, ordered that Geraldo Rivera’s microphone be cut off after Mr. Rivera angrily defended the Obama administration against charges levied by others on Fox. So says a forthcoming book about the 2012 campaign by Jonathan Alter, a columnist for Bloomberg View and a contributor to MSNBC, a Fox competitor.

The book, “The Center Holds: Obama and His Enemies” (Simon & Schuster, $30), which is set to come out June 4, includes a chapter about Fox’s influence on the campaign. Mr. Alter homes in on the channel’s extensive coverage of the Obama administration’s handling of the attacks on a United States diplomatic mission and C.I.A. outpost in Benghazi, Libya.

“Roger Ailes covered the Benghazi story as if it were Watergate just before Nixon’s resignation, with almost wall-to-wall coverage,” Mr. Alter writes before describing Mr. Rivera as the only Fox anchor who was “allowed to offer a dissenting view.”

Mr. Rivera did so on the conservative morning show “Fox & Friends” on Nov. 2, the Friday before Election Day. As the three hosts criticized the administration for failing to save the ambassador Christopher Stevens and three other Americans who died in Benghazi, Mr. Rivera protested. He accused the co-host Eric Bolling of lying, calling him “a politician trying to make a political point.”