WASHINGTON – Perhaps Dan Rather should have taken his own advice: “One’s reminded of that old saying, ‘Don’t taunt the alligator until after you’ve crossed the creek,'” the veteran broadcaster said on Election Night.

Mr. Rather announced yesterday that he will step down in March as anchor of “CBS Evening News.” The announcement came just weeks after bloggers backing President Bush successfully pressured him and CBS to retract an unsubstantiated pre-election report casting aspersions on Mr. Bush’s record in the Air National Guard. That reversal was humiliating in light of Mr. Rather’s firm defense of the anti-Bush report for days after it was challenged.

One of the bloggers who first questioned the authenticity of the documents on which the National Guard story was based described yesterday’s announcement as “half a victory.”

The bloggers expressed disappointment on learning that Mr. Rather will stay on the CBS payroll as an investigative correspondent for “60 Minutes” and its Wednesday night companion program, “60 Minutes II.”

Mr. Rather made his announcement in the CBS newsroom in New York, where he told staff that he will leave the network’s nightly news show March 9 – the 24th anniversary of his replacing the legendary Walter Cronkite in the anchor’s chair.

In response, news staff gave Mr. Rather’s signature “hip hip” three cheers and then returned to work without asking questions.

“It feels like a victory,” one online commentator, William Ardolino, told The New York Sun. “But it is too little, really.”

Mr. Ardolino runs the INDC Journal blog, which, along with three other Web commentaries, pulled apart the authenticity of the documents, questioning such elements as whether their type font could have been available on a Vietnam-era typewriter available to a commanding officer of Mr. Bush’s in the National Guard.

The blogger said a “real victory is dependent on the results of the investigation” that CBS is conducting into the story. That investigation, which is being overseen by a former Republican attorney general, Dick Thornburgh, is to report its conclusions soon.

A CBS spokesman insisted Mr. Rather’s departure was “independent of that investigation.”

In announcing the change, the 73-year-old Mr. Rather made no mention of the election story, saying he had discussed with CBS executives months ago the question of when he should vacate the anchor’s chair.

“I have always been and remain a ‘hard news’ investigative reporter at heart,” he said. “I now look forward to pouring my heart into that kind of reporting full-time.”

Mr. Rather added: “No matter what you hear elsewhere, this was a mutual decision.”

He said nothing is more important to him “than how honored I am to work with the greatest news organization in the world.”

According to the author of a book on “60 Minutes,” David Blum, CBS had wanted the veteran newsman to leave the anchor chair for some time – for months before the National Guard story was aired.

Mr. Blum, who is also a contributor to the Sun, told Fox News: “CBS always wanted, at least in recent years, to move Rather out, bring in a successor, and shore up the ratings. They’ve been in the third position for a while now. Nothing really happened that wasn’t anticipated.”

Others questioned whether the National Guard story hastened Mr. Rather’s departure.

“Dan had hung on for years and the National Guard story gave management the opportunity they needed,” a CBS executive told the Sun.

In a statement, the chairman of CBS, Leslie Moonves, praised Mr. Rather for his 42 years at CBS News.

“He has been an eyewitness to the most important events for more than 40 years and played a crucial role in keeping the American public informed about those events and their larger significance,” he said.

Mr. Moonves provided no indication as to who might succeed Mr. Rather. One name circulating in press circles last night was John Roberts, a journalist who is considered by some to be as liberal as Mr. Rather. Another name that has been mentioned is that of correspondent Scott Pelley. Both work for CBS.

Recent months have not been easy for Mr. Rather, who came in for criticism from CBS colleagues for the National Guard story. The veteran editorialist for “60 Minutes,” Andy Rooney, recently said on CNN, “Dan is transparently liberal.” Yesterday, Mr. Rooney said vacating the anchor’s chair was “a good thing to do.” He added of Mr. Rather: “He has had a good run.”

Mr. Rather’s announcement sparked fierce arguments yesterday on cable and radio talk shows about whether the newsman had been a biased anchor. CNN’s “Crossfire” co-host, Tucker Carlson, argued that Mr. Rather “had not covered the news, he had subverted it.” The host of NPR’s “On the Media” program, Bob Garfield, defended Mr. Rather, saying conservative critics fail to appreciate that “the values of journalism overlap the values of liberalism,” with both questioning authority and caring for the afflicted.

Mr. Rather, a Texan whose tenure on the anchor’s chair was five years longer than Mr. Cronkite’s, was notorious for his folksy imagery.

There were eight samples of Ratherisms involving heat and fire alone on his Election Night broadcast three weeks ago. He said the race was “hotter than a Times Square Rolex,” for example, and he told Kerry aide Joe Lockhart, “I know that you’d rather walk through a furnace in a gasoline suit than consider the possibility that John Kerry would lose Ohio.”

At the same time, since the 1960s Mr. Rather was frequently at the center of battles about press and broadcast values. He clashed publicly with President Nixon and with the first President Bush.

Last night, the bloggers who had demolished the National Guard story critical of the president warned that their campaign against CBS would not cease until action has been taken against the story’s producer, Mary Mapes, and CBS News’s president, Andrew Heyward.

“The results of the investigation and resulting action will be crucial. Mapes must be dismissed; Heyward needs to go as well. If CBS doesn’t take appropriate action, the ‘internet jihad’ is back on the front burner,” Mr. Ardolino wrote on his blog.

With yesterday’s announcement, Mr. Rather becomes the second of the three major networks’ anchors to step down. NBC’s anchor, Tom Brokaw, is being succeeded by Brian Williams. ABC’s Peter Jennings endures.