One night last month, Roger Ailes stood before a crowd of Fox News employees gathered at Chelsea Piers in Manhattan for a celebration marking the channel’s 15th anniversary. “Our prime time is just unbeatable,” he told them.

“Our competition has collectively changed their prime-time lineup in this period of time,” he continued. “We’ve done it a few times. They have collectively changed it 63 times. Shows, stars — I mean, it’s sad, you know? I called and asked them all to move to the second floor wherever they were working. Because when they jump, I don’t want it to hurt.”

Ailes is not a man ashamed to gloat. And, though he is perhaps prone to hyperbole, his pride is certainly not without reason: Fox News Channel came out of nowhere to beat cable news rival CNN in ratings after just five years in existence. In the third quarter of 2011, it averaged 1.9 million viewers a night, more than MSNBC and CNN combined. It outpaces competitors in revenue. It regularly ranks among the top five cable channels during prime time, while CNN and MSNBC often can’t crack the top 20. And it has, as Ailes put it, “changed the face of journalism forever.”

Whether that’s a good thing — for journalism or the American public — is the subject of debate.

Brit Hume had been ABC News’s White House correspondent for eight years when he got wind in 1996 that Rupert Murdoch was planning a 24-hour cable news channel. He heard that Ailes was going to lead the venture. Ailes had begun working in television production at age 25 before becoming an adviser to presidents Richard Nixon, Ronald Reagan and George H.W. Bush and ultimately signing on as president of CNBC. “Oh, boy,” Hume remembered thinking. “This is probably gonna go somewhere.”

Over dinner at the Four Seasons in Georgetown, Ailes made his pitch. “The news as it was being presented by all the major mainstream outlets was not balanced,” Hume recalled Ailes saying. “And there was a whole lot of opportunity to do stories in a different way — a legitimately different way, and to do stories that others were not interested in. And he also believed that there was an insufficient number of conservative voices being heard — very few at the major channels.”

Hume, of course, was employed by one of those major channels. “And I had become more conservative in my outlook and I could see that as clearly as anything,” he said. His wife, Kim, signed on as Fox’s Washington bureau chief and helped prepare the channel’s launch on Oct. 7, 1996. When Hume’s contract came up in December, he joined as managing editor.

Since then, Fox has become a very real force in America’s culture and politics. It has altered the national dialogue with its different sensibilities and given conservatives a platform. It has become the source of great equity or great evil, depending on your perspective.

Fox veterans speak with dreamy nostalgia about the early days, which they characterize as a David-vs.-all-the-Goliaths experiment. Though Murdoch spent tens of millions to launch, Fox staffers remember having a two-person crew, when the other networks had seemed to have a dozen people per crew. They were operating with a try-this mentality and doing it with the awareness of a protective, if frustrating, fact: No one’s really watching.

Murdoch was paying cable companies to pick up the new network, but many markets declined. “In the beginning, it was strange, because no one could see what we were doing,” said Jay Wallace, who started as a 25-year-old overnight producer and is now vice president of news.

News as entertainment

Fox staffers point to coverage of various events that catapulted the network to prominence. Perhaps it was the Monica Lewinsky scandal, the 2000 Florida recount, Sept. 11, 2001, or Hurricane Katrina. By its 10th anniversary, executives had put together a video montage of quotes from early critics who pooh-poohed the channel’s chances. The not-so-subtle message: “Eat crow, wouldya?”

Among the things that set the channel apart was an underlying belief that news needed to double as entertainment. Even his sharpest critics agree that Ailes’s skills as a TV producer are unsurpassed. He made the graphics flashier, the segment titles more arresting and pushed the pacing to match that of a multi-tasking public.

He had a discerning eye for talent, signing Sean Hannity, Bill O’Reilly, Shepard Smith and Greta Van Susteren. And he pushed his new team to alter the role of the on-air journalist.

“The reporter and the host became personalities,” said Tom Goldstein, director of media studies at the Berkeley Graduate School of Journalism. “They became almost more important than the stories.”

Other news channels followed suit, adding visual pizazz, such as the news ticker that Fox began running after the Sept. 11 attacks. They also gave their journalists more leeway to emote, though none to the degree of Fox.

Sometimes, explained veteran anchor Shepard Smith, his team has worked on a story for months, “and I’ll do anything to get you to watch it. . . Anything short of altering the truth, we’ll do.”

Critics say that includes sensationalism, fear-mongering and partisanship. “Fox News in essence sort of became a right-wing talk radio station but with pictures,” said Steven Livingston, a media professor at George Washington University.

But for all those who deplore the network, there’s no debating that its approach has attracted a large and loyal cadre of viewers.

“They provided a source for news to a lot of folks who were disgruntled with their choices up to that point,” said Jeffrey McCall, a communications professor at DePauw University. Now, “if you want to run for office or if you’ve got policy moves you want to make, at some point you’ve got to address the audience that is watching Fox. They’ve put themselves in a position where they can’t be ignored anymore.”

Stocking up from the right

Fox’s biggest departure from its competitors was its political orientation. The network programmed mostly news during the day and opinionated talk during prime time. While it hired a few Democrats, such as Joe Trippi and Evan Bayh, it stocked its editorial pundit ranks with prominent Republican officials and candidates.

Before the 2008 election, for instance, Fox News hired George W. Bush’s political adviser, Karl Rove, as an analyst. And it has rotated through contributors who were expected to be Republican contenders in 2012, including Mike Huckabee, Rick Santorum, Newt Gingrich and Sarah Palin.

Fox officials say those hires are just smart business. Ailes recently told the Associated Press that he hired Palin “because she was hot and got ratings.” Fox officials said Ailes was not available to comment for this story.

The conservative slant of Fox’s opinion programming had an effect on the news landscape: Coveting Fox’s ratings success with that formula, MSNBC eventually co-opted it, becoming what it characterizes as a “progressive” network. And in time, MSNBC’s prime-time ratings grew to beat those of CNN, which claims a middle-of-the-road approach.

Livingston said that to understand Fox’s success, it’s imperative to look back to the conservative crisis after Watergate. In determining what caused the fall of Nixon, conservative leaders pointed their fingers at the media, think tanks and other political institutions that held influence. They decided that the answer was to create alternative institutions, such as the Heritage Foundation, and to establish a stronghold in talk radio, Livingston said.

Fox News “speaks to that need for framing cultural and political debate in America for a culturally conservative perspective,” he said.

Among its points of pride — and its critics’ biggest vexation — is the network’s story choice. Fox deliberately focuses on angles that differ from what competitors are pursuing. Hume pointed to coverage of the Duke lacrosse rape case, in which Fox was skeptical of the alleged victim’s claims. In the end, the charges against the players were dropped.

“They’re putting stuff out there that otherwise would never get airtime,” said Brent Baker, vice president of the conservative Media Research Center. He cited the Van Jones controversy. The Obama White House adviser was ultimately forced to resign over his past association with a group that had Marxist roots and his signature on a petition questioning whether the Bush administration was behind the Sept. 11 attacks.

There has been less vindication on other Fox story lines, including skepticism about whether President Obama was born in the United States, which ultimately resulted in the White House’s release of his birth certificate in April. The network was also criticized for its pundits’ frequent use of the term “death panels” in discussing a version of Obama’s health-care-reform proposal that included voluntary end-of-life counseling.

For Robert Greenwald, the liberal director of a highly critical 2004 documentary on FNC called “Outfoxed: Rupert Murdoch’s War on Journalism,” the problem isn’t just what the network covers. “The biggest thing is the stories they won’t cover,” he said. “Over the years, anything that ran counter to the preferred conservative image would not be covered.” For example? “The consequences of the Iraq war.”

‘We really try to be balanced’

During phone interviews, Smith and fellow anchors Bret Baier and Megyn Kelly each said they don’t approach the news from a conservative perspective. “We go into the morning meeting every morning and determine what’s news — what’s getting attention and what’s not getting attention and should,” said Baier. “We really try to be balanced.”

“People like to label coming from a different viewpoint as conservative,” said Wallace, the vice president of news. “But I don’t think there’s anything wrong with asking questions that aren’t being asked by other people. That doesn’t necessarily make it conservative.”

Officials at Fox say there is a distinct line between their news reports and opinion shows. “Sean Hannity is, without question, a right-wing pundit and I do the news,” explained Shepard Smith. “I’m just looking for facts.”

But critics insist there’s a bias in Fox’s reporting — much in the way there has long been an accusation that mainstream media approach stories from the left. The network came under fire, for instance, after the release of a leaked memo from a top Washington editor, Bill Sammon, dictating that Fox reporters accompany any mention of climate change with skepticism about the science demonstrating its existence, a matter on which Fox officials have declined to comment. And in news reports, Baier has referred to Al Gore as a “global-warming alarmist.”

Hume said the editorial segments “have more conservatives on the air by some measure, than any other channel,” but on news segments, “what you see is a lot of straightforward news done by a lot of pretty qualified correspondents and anchors who are doing balanced discussion segments.”

A 2006 study by professors at UC-Berkeley and Stockholm University estimated that Fox News swayed between 3 and 8 percent of its viewers to vote Republican in 2000.

“The media really does have a strong effect on the way we think and vote,” said Tim Groseclose, a political science professor at UCLA and author of the new book “Left Turn: How Liberal Media Bias Distorts the American Mind.” “I think Fox really has moved people, at least slightly, to the right. People think a little more conservatively and I think our policies are a little more conservative than they would be otherwise, without Fox News.”

Fox has “certainly opened up and enlivened and perhaps brought into political debates people who otherwise would not have been involved,” said GWU’s Livingston. “That’s one point. The other point is, ‘Is it always a good thing that that is true?’ ”

Livingston points to a 2010 University of Maryland study that found that Fox viewers are the most misinformed of all news consumers. They were significantly more likely than non-viewers to believe that scientists don’t agree that climate change is occurring, that the auto bailout happened solely under the Obama administration and that it’s unclear whether Obama was born in the United States.

Fox detractors often blame the network for the polarization of the country. But Shanto Iyengar, a political science professor at Stanford, said it’s just part of a pervasive echo-chamber effect. “People like to avoid dissonant messages,” he said. “If we believe X, we don’t want to encounter information that is not X.” Now, with so many choices of where to get information, consumers can pick what they want to watch.

Hume thinks Fox thrived simply because it offered an alternative people wanted. “The principal effect is that we broke the monopoly on a certain kind of news coverage. . . . I think it’s changed the atmosphere to some extent in the country. It’s a great business success story. It’s also, in my opinion, a journalistic success story.”

The millions who watch, at least, seem to agree.