ABC is not alone in wanting to distinguish itself. For the first time in the history of the iconic evening network news broadcasts, all three are trying to present clear choices, built around the very different identities of their anchors. ABC emphasizes stories it considers most relevant to its viewers’ lives, plus lighter news and features, in a program built around the dramatic (some say melodramatic) delivery of Diane Sawyer. CBS delivers a serious program on steroids, in harmony with Pelley’s buttoned-down personality. And the ratings leader, NBC, has staked out the middle ground, with an anchor, Williams, who has news credibility but no aversion to feature stories, and who loves to show off his wry sense of humor.

There’s a lot at stake. The three network newscasts have lost enormous chunks of their audience in recent years, due to harsh demographic realities: Their viewers are dying off, and younger consumers haven’t established the same news habits as their elders. Then there’s the fractionalization of the marketplace, brought about by the proliferation of cable news outlets, on-demand Internet news sites, and social media optimized for quick, mobile consumption. Where news consumers once had only a handful of options, their choices now are virtually unlimited, and they can mix and match the news they want to see. Even so, network news remains formidable. Together, the three network newscasts still attract more than 23 million viewers every weeknight—almost a third of the people watching television at 6:30 in the evening. Each broadcast has an audience bigger than any other single source of news.

In fact, with all the attention given to cable news, it’s worth noting that even the lowest-rated network newscast alone has an audience more than two-and-a-half million people larger than the combined audiences of the 6:30 news programs at Fox News, CNN, HLN, MSNBC, and CNBC. The problem is that, according to network research, more than 80 percent of their viewers say they have “seen the news” (on cable, on local television, on the Web, via social media, in newspapers) before the network newscasts air. If they are to keep viewers, or gain new ones, the network newscasts cannot afford to be seen as “more of the same.” They must offer more than a recitation of the day’s events, which viewers may feel they already “know.”

In the golden age of network newscasts, 90 percent of the people watching television at 6:30 p.m. were watching “the news.” With virtually no news competition, and working in the tradition of serious newspapers and radio broadcasters, all three TV networks aired broadcasts that dealt with “important news,” lightened only by a “kicker” at the end. There was little hesitation about forcing viewers to “eat their spinach,” and not much debate about whether viewers should be given what they “needed to know” or what they wanted (which was presumed to be less important). Producers and editors spent a lot of time worrying about whether their selection of stories would match up to the next morning’s New York Times. Which newscast you watched depended almost entirely on which local television station you were watching when the news came on, and whether you liked Walter Cronkite better than Chet Huntley and David Brinkley, or Peter Jennings better than Dan Rather or Tom Brokaw. Until relatively recently, it was possible to complain that all three networks were doing essentially the same broadcast.

Brian Williams remembers it as “the kind of groupthink image that for years we all know existed, where you looked at all three monitors and sometimes shot for shot, stride for stride, it’s as if we Xeroxed the first bloc and sent it across town and said, ‘Okay, so we’re in agreement this is what we’re going to do tonight.’ ”

Paul Friedman is the Professional in Residence at the Quinnipiac School of Communications. Over a span of 40 years, he worked at all three network news divisions, including positions as senior producer of NBC Nightly News, executive producer of Today, executive producer of ABC World News Tonight with Peter Jennings, and executive vice president of CBS News.