Brian Williams still has nightmares about New Orleans, and on Thursday morning he woke up with an irritated throat from being around the dried mud that continues to cover the Ninth Ward.

He had returned the night before from his sixth visit in three months to the devastated city, and by the 2:30 p.m. editorial meeting was again pushing to lead "NBC Nightly News" with the aftermath of Hurricane Katrina.

"We will never forget this story," says Williams, who even while relaxing in his office keeps his yellow-and-blue tie tightly knotted and the French cuffs of his crisp white shirt fastened. "It looms too large in my life. Journalists can be marked by the events they cover. I will always feel like a bit of a witness."

One year after succeeding Tom Brokaw, Williams, 46, has changed the job in several ways, most notably by writing a daily blog, poring over readers' e-mail and occasionally dashing off answers. But from his first foreign foray as anchor, when he was summoned to cover the Asian tsunami during a New Year's Eve dance with his wife in the Caribbean, Williams has been defined by disaster.

"I noticed a change in his professional demeanor as soon as he came back from the tsunami," says NBC News President Steve Capus. "Before, he was kind of approaching it like he was filling in for Tom. When he came back, it was very clear, 'This is my broadcast.' He found his voice."

Such trips -- Williams was among the first to report on the human misery in the Superdome -- seem to have quieted critics who tended to dismiss him as an attractive lightweight. And Williams, who fires off BlackBerry messages to Executive Producer John Reiss at 2 in the morning, hasn't let up. "He has really ridden me to make sure we have almost no broadcasts without something Katrina-related," Reiss says.

Williams has established himself as the top-rated anchor just as the other broadcast networks are struggling with succession. When Williams took the anchor chair last December, he was competing against Peter Jennings and Dan Rather. But Jennings's death and Rather's early exit after the President Bush/National Guard controversy cleared the field for the man who had been waiting in the wings for years.

"I gave him a sleeping bag," Brokaw says. "I didn't know he'd have so much opportunity to use it."

Says Williams: "Tom did everything he could while he was in the chair to say to our audience, 'Please transfer your affection, loyalty and trust to this guy.' I owe so much of how smoothly it's gone to him."

Williams leads the pack with 9.5 million viewers over the past three months, compared with 9.9 million during Brokaw's last three months. ABC's "World News Tonight," with fill-ins Bob Woodruff and Elizabeth Vargas, averaged 8.5 million, down from the same period last year, while the "CBS Evening News" has gained a bit under Bob Schieffer, to 7.2 million viewers.

Williams is driven -- instead of power-lunching, he often brings back a pizza slice from his favorite joint near Rockefeller Center -- and likens his life to that of the plate-spinning entertainer he once watched on Ed Sullivan. He is undoubtedly the only network anchor in history to be a NASCAR fan (and pal of the late Dale Earnhardt), White House and Supreme Court buff (he has a photo of the Warren Burger court signed by every justice), former volunteer firefighter and member of the Council on Foreign Relations (where he recently interviewed Joe Biden). So far, at least, Williams hasn't let any plates crash to the floor.

With a packed schedule, why does he spend time blogging? "It lets people in on our editorial process," Williams says. "I take our own folks to task when I think we've failed the evening before. Viewers deserve to know more about our machinations." During President Bush's trip to Latin America last month, Williams wrote that "we dropped the ball" on the president's mixed reception, blaming himself and some of his colleagues.

The blog also gives him a chance to vent. He wrote that setting up an interview with New Orleans Mayor Ray Nagin took "hours of planning, cajoling. . . . We've conducted interviews with presidents of the United States with less discussion of camera angles, walking distances, duration, lighting and timing."

Williams does a daily introduction for a Webcast version of "Nightly News" and takes home as many as 750 e-mails a night in a blue folder. "These are the customers," he says. In fact, his trip to Mississippi to examine hurricane damage was prompted by e-mail from people in the state who felt ignored with all the media focus on New Orleans. He has also added a periodic segment called "Making a Difference" in response to complaints that television rarely covers good news.

When Williams is in Louisiana, he seems to don a bit of the crusader's mantle. "The damage here seems so fresh. . . . These days in the Lower Ninth Ward, it's the neighborhood that's been left to die," he reported Wednesday, signing off from "this very sad place."

Changing a half-hour newscast in an era of declining news audiences is a difficult task, and the daily editorial conference makes clear how many people are clamoring for the limited airtime.

At Thursday's session, more than a dozen producers run through the stories that could follow Martin Savidge's piece on more people than expected showing up to check out their Ninth Ward homes: Andrea Mitchell building on a Los Angeles Times scoop about the Pentagon planting good-news stories in Iraqi newspapers. Two competing pieces from Iraq (one draws groans because it is 2 minutes 20 seconds, an eternity by network standards). Robert Bazell on World AIDS Day. Tom Costello on identity theft. Pete Williams on a gang of jewelry thieves.

Producers pitch a number of briefs: A South African court legalizing gay marriage. Two U.S. allies withdrawing troops from Iraq. Bush being called for jury duty. They kick around "ribbons," or graphic headlines, for each piece: "War of Words" wins out over "Fit to Print" for Mitchell's story on the Pentagon planting and paying for news in Iraq.

The plan is to devote the last segment to a scene that Williams stumbled upon in New Orleans: a band playing in the street outside K-Paul's restaurant. Another producer suggests a kicker about a cat that mistakenly got shipped to France and is being reunited with its Wisconsin family. Williams, a self-described dog person -- he keeps a picture of his mutt Lucy on his cell phone -- is unenthusiastic. "Yeah, it'll run at 6:28 on every local program," he says.

Another reason the cat item won't fly: Williams believes a post-9/11 newscast should be serious. "If you want sweetness and light, there are 500 cable channels set up to deliver entertaining images," he says. "We don't do light stuff. I won't allow it."

But there are a few wry moments, or as Reiss puts it: "I leave room in the broadcast to just let Brian be Brian." One opportunity came when a chunk of marble fell from the Supreme Court's facade. Williams wrote: "When you see this next story, we do not mean to imply that justice is crumbling in this nation, not even close."

After the editorial meeting, Williams begins tapping out his blog entry -- about, naturally, the New Orleans trip. He describes driving down a dark road and finding it blocked by a three-bedroom house. (His computer, wired to measure his spoken words for broadcast -- his pace is slightly faster than Brokaw's -- times the first part at 2 minutes 33 seconds, even though this is only for Web surfers.) Williams also outlines plans for the upcoming newscast. This reporter's visit is duly noted.

As the 6:30 newscast approaches, Williams grabs a power bar and tweaks the scripts. At 5:14, he starts writing his closing piece on the New Orleans band, capitalizing words for emphasis: "It just might be a sign of SOMETHING -- a band has set up in one of the few bright lights of the French Quarter, and by doing so, they've become a bright spot in a city TRYING to emerge from some VERY dark days." He finishes in six minutes.

There are last-minute judgment calls: Can they describe the Pentagon's Iraq media offensive as "propaganda"? Producer M.L. Flynn wants to talk to defense correspondent Jim Miklaszewski about his sourcing but sees on a wall monitor that he is holding forth on MSNBC's "Hardball."

Williams questions the value of touting an NBC Web posting on ways to avoid identity theft. "Kill it," he says. The show winds up 20 seconds short, so Reiss adds a brief on new economic figures.

Williams heads for the studio moments before airtime. The newscast seems to go flawlessly, but Reiss orders a retake for the top of the 7 p.m. feed to Washington and other markets. The opening picture for Williams's first story showed Mississippi, not New Orleans.

Missing from the program, as on many network newscasts in these days of shuttered bureaus, is any report about a foreign country other than Iraq. Williams acknowledges the trend and says he has pitched the network on a trip to China.

In private, Williams is funny and irreverent -- he's held his own on Jon Stewart's "Daily Show" -- but as a newscaster he tends to be dry, straightforward and a bit formal. With the other networks considering multi-anchor formats -- unless CBS is able to lure Katie Couric from NBC -- Williams could well be the last traditional anchor. It is a description he does not dispute.

"There is a huge market for the broadcast people grew up with, delivered in a modern-day style," he says.

Williams on the set of No. 1-rated "NBC Nightly News" a year after he took over from Tom Brokaw.After a year as the anchor of "NBC Nightly News" Brian Williams's devotion to the Gulf Coast story has quieted critics who tended to dismiss him as an attractive lightweight.