The death of newsman Peter Jennings (search), following the recent resignations of Tom Brokaw (search) and Dan Rather (search), has once again called the future of network news into question.

For more than two decades, the three network anchors were the trusted faces of nightly national news, broadcast conveniently at dinnertime.

Brokaw, 65, retired from NBC’s "Nightly News" (search) in November, and Rather, 73, signed off from "CBS Evening News" (search) in March.

With Jennings’ death on Sunday at age 67 — he hadn't been seen on ABC’s "World News Tonight" (search) since April, when he announced he’d been diagnosed with lung cancer — an era has abruptly ended.

The "Big Three" network newscasts draw more than 25 million viewers each night, but viewership has dropped by 34 percent since 1993, thanks largely to the 'round-the-clock news available on 24-hour cable channels and the Internet.

"Jennings’ death is just one more piece of evidence that the decline has to continue — there is simply no reason for a 30-minute newscast to matter as much as it did when you can get news at any time from any source," said media analyst Eric Burns, host of "FOX News Watch."

But, added Burns: "I don’t think there will be a point when it will suddenly drop off. … They still have huge audiences. In terms of actual numbers, there are still so many more people watching Bob Schieffer than any show on cable."

New Faces

Schieffer has taken over as a temporary replacement for Rather at CBS, and the network has been in talks with others — including Katie Couric (search), co-host of NBC’s "Today" show — to fill the spot permanently.

"We’re obviously in the middle of reformulating CBS News," said spokeswoman Sandy Genelius. "There’s no announcement on that, but hopefully soon. … We think the future of network news is very bright."

At NBC, Brian Williams (search) has sat in the anchor chair since Brokaw’s departure in what has turned out to be a fairly smooth transition.

And since Jennings’ illness forced him to vacate his seat at ABC, "Good Morning America" co-host Charles Gibson (search) and reporter Elizabeth Vargas (search) have alternated at the helm of "World News Tonight."

When asked by The Associated Press who would be Jennings’ permanent successor, ABC News spokesman Jeffrey Schneider said, "There will be a time to discuss that. This is not that time. When we emerge from this difficult time and are prepared to say something, we will."

For now, Gibson and Vargas will continue to fill in for Jennings. It's almost certain the next "World News Tonight" anchor will come from within ABC News.

Gibson, 62, is a solid contender, familiar to ABC viewers as the longtime anchor of "Good Morning America." He anchored ABC's live coverage of Pope Benedict XVI's selection and last month's launch of the space shuttle Discovery.

But moving Gibson into the evening news anchor role would take him off "Good Morning America," which has been surging in the ratings and giving NBC's "Today" its first serious fight in a decade.

Leaving Gibson in the morning would signal the increasing importance of the breakfast hour time slot, which is already a big profit staple.

Vargas, 42, lacks Gibson's experience but could attract some younger viewers. The evening news has one of television's oldest audiences.

ABC's anchor bench also includes people like Bob Woodruff, John Donvan, George Stephanopoulos, Dan Harris and Cynthia McFadden — all of whom have also tested as potential "Nightline" anchors for when Ted Koppel leaves at the end of the year.

One approach could be to give Vargas the "World News Tonight" job and have Gibson anchor many of the big breaking stories. On CBS, Schieffer has occasionally given way to John Roberts and others on big stories.

ABC's rivals have shown sharply different approaches in their transitions to new anchors. NBC planned the switch from Brokaw to Williams with machinelike efficiency, and Williams has kept Brokaw's top spot in the ratings, with nearly 10 million people tuning in each weeknight.

CBS appointed Schieffer as Rather's temporary replacement for a few months while promising "revolutionary" change at the third-ranked newscast. But a few months has now become six, and no permanent plan has been announced.

End of an Era

The Rather-Brokaw-Jennings triumvirate held steady — covering everything from the fall of communism and the Sept. 11 attacks to the O.J. Simpson murder trial — as the world of news changed around them, driven by the spread of cable and the Internet.

Jennings' death, together with the departures of Brokaw and Rather, means "a whole bunch of people are going to be writing obits about the network evening newscasts," said Joseph Angotti, a former NBC News producer and lecturer at Monmouth College in Illinois.

"And, as they have been in the past 30 years, they're premature," Angotti said.

But some say that at the very least, it could be the end of the celebrity anchor, or the anchor who delivers the news with what has been dubbed "voice of God" authority.

"The network TV news can’t make you a star now," Burns said. "It doesn’t matter who the anchor is or whether you have a star anchor. There’s no way in the world to reverse the [viewership] decline."

USA Today quoted NBC Universal president Jeff Zucker as saying Monday that "network news will still play an incredibly important role in this country, but the world that Peter, Tom and Dan began covering 25 years ago isn't the same world today. Technology, lifestyle and what constitutes news have all changed dramatically. I'm not saying that it is better or worse. I'm just saying that it's reality."

No matter what the future holds for network news, analysts predict it won’t be disappearing any time soon — if ever.

"I don’t believe any network has seriously considered getting rid of its newscast altogether," Burns said. "These shows are going to be around for a long time."

The Associated Press contributed to this report.