ABC News changes mark a big 'turning point'

David Muir tweeted that Wednesday was an "incredibly humbling day," as he was named to succeed Diane Sawyer as anchor of ABC's World News. But the day was equally humbling for the evening newscast: George Stephanopoulos, and not Muir, will become the "chief anchor" at the network, the go-to guy for major breaking news and political coverage.

The symbolic shift marks the first time that someone other than the evening news anchor will be the main public face of a broadcast network's news team, sending the strongest signal yet that the 30-minute nightly newscast, once the flagship of a news division, is far from the most important.

Sawyer, 68, is departing World News in August to anchor prime-time investigations and interview specials for the network, so ABC is effectively splitting her job in half: Muir, 40, a World News correspondent, weekend and substitute anchor and 20/20 host, will take over as primary anchor on Sept. 2.

But Stephanopoulos, 53, who hosts Good Morning America and Sunday morning public-affairs show This Week, will assume the network's "chief anchor" role, guaranteed in his latest contract extension signed earlier this year, and triggered by Sawyer's departure. (He already heads ABC's election coverage.)

"It's a significant turning point," says network-news analyst Andrew Tyndall, that follows what he sees as a shift in World News' focus from serious coverage to a "more human-interest survey of what's buzzy."

But Richard Wald, a former ABC News executive who's now a professor at Columbia University's School of Journalism, says the anchor split says less about the stature of the evening newscast than about the personalities involved.

"George is the more powerful anchor; he's a major news person and by far more experienced than David," he says. And his new role provides him with greater stature while still protecting GMA, the news division's most important profit engine, which overtook NBC's Today show last year.

Sawyer's departure comes as World News and its counterparts have made ratings gains this season in a slight reversal of a long-term decline. Sawyer is averaging 8.1 million viewers, up 4% to its biggest total since 2007-08, though top-ranked NBC, along with No. 3 CBS, have posted 6% gains. (ABC bested NBC in May among adults ages 25 to 54, the primary ad target for news shows.)

Her eventual exit has been whispered about for some time. But why now? She wouldn't say: Neither the anchors nor ABC executives were made available for interviews. "As much as she loved leading World News to new heights…Diane decided that now is the moment to concentrate full time on tackling big issues in new ways," ABC News chief James Goldston said in a statement.