The Walter Jenkins episode tells you a lot about Lady Bird Johnson, says biographer Jan Jarboe Russell.

Jenkins had worked for Lyndon Baines Johnson since both were young men on Capitol Hill. He was loyal, steadfast and skillful -- but about a year into LBJ's term as president, he was arrested in a YMCA restroom for a homosexual act. Clearly, he had to leave his job as White House chief of staff. But Lady Bird, in a conversation captured by Johnson's ubiquitous taping system, urged her husband not to abandon their old friend and his wife, and said she wanted to give him a top job at their television station in Texas.

"You won't have your license five minutes," LBJ said.

"I'd just rather offer it to them and let the license go down the drain," Lady Bird answered.

The discussion went back and forth, LBJ reminding her of the coming election and her public duty as first lady; she saying they could lose the support of others close to them if they treated a longtime associate badly.

Once "she realized that she'd pushed her husband as far as she could," Russell writes, she concluded the conversation with sympathy and love. "My heart breaks for you, too," she said.

"That is their entire relationship in a nutshell," says Russell. "He seeks her advice, she gives him great advice, he ignores it, and at the end she says, `I love you.' "

Russell, a 48-year-old journalist from Texas, thinks Lady Bird Johnson has been undervalued and underestimated by her husband's biographers. In her new book, "Lady Bird: A Biography of Mrs. Johnson," she portrays a woman of great intelligence and skill, and suggests that the psychologically complex LBJ -- demanding, needy and brilliant as he was -- could not have achieved and survived as much as he did without her.

LBJ may have dictated to his wife how she should look, chose her dresses, instructed her to pull up her slip or put on lipstick, and pretty much mandated the terms of their 38-year life together, but Lady Bird wielded a quiet but significant power. She was the first first lady to campaign separately from her husband and the first to earn a million dollars on her own.

The author sees Lady Bird through the lens of contemporary feminism, but with profound respect for the professionalism and dignity with which Lady Bird endowed a now old-fashioned job description: wife.

The Johnsons were a shock when they hit the national stage in 1960, when LBJ ran as John F. Kennedy's vice president. A family whose members all had the same initials! And those accents! Somehow Kennedy's Boston twang seemed more palatable -- in those days a Southern accent was a metaphor for stupidity and gaucherie. LBJ, compared with the seemingly classy Kennedys, came across as coarse and vulgar; his wife as a dutiful adjunct with an immovable hairdo, a plebeian next to elegant and silent Jackie.

But as time goes by, and politicians become more synthetic and their wives more opaque, the Johnsons look better and better. His vulgarity seems more like honesty. And Lady Bird, now 86 and ailing -- she was hospitalized for observation yesterday after fainting at home -- has rightfully earned respect and affection for her accomplishments in business and conservation and her smarts, as well as for her impeccable manners.

Russell, who has covered Texas and its politics for 25 years, decided to write the biography after interviewing Lady Bird for a Texas Monthly article in 1993. She spent more than four years on the book, three of them with her subject's cooperation -- but not approval.

"When I first talked with her about the book, she had said my book should be an `independent work of history,' and that she wasn't going to stop me but she wouldn't help me. Remember, she majored in journalism."

Their interviews had covered the years up to 1951 when Mrs. Johnson cut off contact. Her letter of dismissal followed a piece Russell wrote for Slate magazine, reflecting on her hours of listening to the LBJ tapes. Among other things, she wrote that "Johnson was the last of the really big hicks," and that the tapes make him sound not like "a giant, but a fearful and uncertain man with a very big voice."

Lady Bird's letter was, of course, polite, but definitive: "Your conclusion about me may well come at Lyndon's expense," she wrote.

Liz Carpenter, Mrs. Johnson's press secretary in the White House and her continuing defender and neighbor in Austin, condemns the book as unfair -- even though the portrait of Lady Bird that emerges is extremely flattering. Russell "never said anything kind about the president," she says. "You just can't ignore his record."

Johnson's older daughter, Lynda Johnson Robb, refused to talk to Russell, and declined through a spokesman to comment on the book. Luci Baines Johnson, who now runs the LBJ Holding Co. in Austin and recently -- at age 50 -- finished her college degree, was interviewed by Russell at some length. She did not return a call to her office.

There's another issue that rankles Carpenter: Russell includes material on Johnson's infidelities, though nothing that hasn't been disclosed previously. "She went out of her way to play up to the current headlines in Washington," said Carpenter. "All this Monica Lewinsky stuff. I don't like it."

Considering all the rumors she left out, Russell was surprised by Carpenter's reaction, but she understands. "For these people, LBJ was not just a man, he was a cause," she said.

"I made a conscious decision to include only the women who had been previously written about. My book is about Lady Bird, not him, and what was important is her reaction to these affairs, which she must have known about at the time."

When faced with evidence that he was carrying on with another woman, Lady Bird ignored it, and thus made it go away -- no doubt aided by the press of that time, (LBJ was president from 1963 to 1968) which never reported a breath of indiscretion about either Kennedy or his vice president. "Fix yourselves, and keep your problems to yourself," she told Russell sternly.

Despite Carpenter's complaint, there is in the book exactly one paragraph on Bill Clinton and his sex scandal.

But Lady Bird and Carpenter are women of a different generation, and that is actually one of the elements that attracted Russell to the project in the first place. One of the first stories she heard about Lady Bird -- long before she'd thought of writing a book -- came from D.B. Hardeman, former top aide to House Speaker Sam Rayburn (D-Tex.). He recalled a time when LBJ was giving a speech and going on too long. Hardeman, an admirer of Lady Bird, saw her make a discreet gesture moving her hand across her mouth.

"She shushed him, as Hardeman put it," Russell said. "I can't imagine doing that; I don't think anyone my age would do that! Even the word `shush' is from another era. But it shows a lot about their relationship."

"My entire growing-up in east Texas, the Johnsons completely dominated public life," Russell said during a recent visit to Washington. "She was by far the most well-known woman. . . . The women in my family all had that same hairdo, and they were like her in that they were running the garden club and the library, managing the husbands and children. I knew they were running things, kind of secretly, but I didn't consider them role models. I wanted to carve out my own identity."

Russell finds the parallels between her life and Lady Bird's intriguing, though limited. They are from the same part of east Texas, a region she describes as "isolated, small, poor and well-mannered," in contrast to the stereotypes of Texas oil money and showoffs. Like Lady Bird, she majored in journalism, and thought of herself as a shy person. But Russell went from college to a job at the Savannah Morning News, while Lady Bird -- disappointing the aunt who had hoped she would become a reporter at The Washington Post -- eloped with Lyndon Johnson when she was 21.

There is another link. Russell's first marriage, which lasted 12 years, was to a Methodist minister, traditionally a semi-public role in which the wife would -- much like a politician's spouse -- serve the husband's career.

"Doing the book did cause me to think about the expectations for wives and how I did not do that," she said. "There is a cost to being that faithful to self. I'm not sure if it's better or worse -- it's a different generation." Russell, who has two children, has since married a doctor and lives in San Antonio.

In today's terms, much of Johnson's dictates to Lady Bird and his flirtatiousness -- such as the time he put his hand under the skirt of a woman seated between him and his wife -- would be cause for divorce. But in the context of the time and their culture, it was not surprising that Lady Bird stuck it out until he died in 1973.

"Was Johnson abusive? The whole culture was abusive, especially to women," said Russell. "I do not see Lady Bird as a victim."

When she asked Lady Bird's contemporaries why they admired her, they'd say, "Her ability to make a life alongside him." When she asked about his infidelity, they marveled at her fidelity.

While Lady Bird's stoicism is emblematic of her whole character, it is, in Russell's analysis, just one layer of the complex connection between the Johnsons. Lady Bird may have defined herself as a Wife -- but within that context she exerted power, however gently. As well as being the first first lady to campaign, she was the first to hold the Bible during the swearing-in -- a small symbol, perhaps, but one that suggested that henceforth first ladies would return to the Eleanor Roosevelt model and leave the Bess Truman, Mamie Eisenhower and Jackie Kennedy helpmate persona behind.

Johnson knew how valuable his wife was, and not just for the modest financial stake she brought to the marriage and subsequently turned into a multimillion-dollar broadcast business by shrewd acquisitions and management. One of her most courageous -- and, in retrospect, amazing -- expeditions was her whistle-stop campaign through the South to sell the 1964 Civil Rights Act.

"During a four-day, 1,628-mile campaign trip through eight Southern states . . . she traveled to cities and towns that were in such racial turmoil it was not considered safe for Johnson to go," writes Russell. "Her message was that the Civil War should at long last come to an end, which could only happen if the South shed its racist past and moved into the modern world."

Despite bomb threats, snubs from local governors, rumors of riots, and heckling from some crowds, the president's wife stayed on message as her 19-car train moved through small and large Southern towns.

She used her Southern charm and her celebrity, recipes for pecan pie, giveaway souvenirs and a team of congressional wives to set the vocabulary of the debate -- segregation must end if the South was to prosper. And the 150 reporters who rode along gave her extravagant coverage.

Among Washingtonians, Lady Bird is especially appreciated in the spring, when the cherry trees she raised money for bloom, and the 2 million daffodils she funded lighten great swaths of our public space. Since her 80th birthday, she has raised $10 million for the National Wildflower Research Center, which she founded in Austin. Her very voice can be heard at the LBJ memorial rock near the Columbia Island Marina; push a button and you'll hear her gracious Southern tones.

Russell says Lady Bird's love of beauty and nature, which came to benefit so many others, stems from early heartbreak -- Mrs. Johnson's mother, Minnie Taylor, died before her daughter turned 6, and she found comfort in the great outdoors.

"Whenever I see those daffodils," said Russell. "I think of a little motherless girl who always looked for the first daffodil of spring and named it queen."

A one-hour interview with Lady Bird Johnson, part of the "American Presidents: Life Portraits" series, will be repeated at 7 a.m. Saturday on C-SPAN.