By Philip Rucker

House Speaker Nancy Pelosi returned home to San Francisco this weekend carrying a red, white and blue pocket card that will help guide her through the August recess. The card lists talking points she hopes will convince everyday Americans of the benefits they could receive under the health-care reform plan she hatched with other House Democrats last week.

Pelosi distributed the cards to all 256 of her caucus members, arming the unruly Democratic majority for battle in their disparate districts across the country. After laboring for weeks in Washington to reach a compromise between liberal and conservative factions of her caucus, Pelosi is taking the fight outside the Beltway, where polls show that her popularity is faltering. She plans to stump for health-care reform in San Francisco, Denver and other cities.

At stake is legislation that could define her legacy as speaker and shape President Obama's political future. Pelosi called health-care reform with a public insurance option "the issue of an official lifetime."

"August will be a month of inoculation against the negative message of the insurance industry," Pelosi said in an interview, resting in a yellow armchair in her stately office, which has sweeping views of the Mall. "It will be a month of education in terms of what is in our bill. It will be a month of communication -- listening, listening, listening to what constituents have to say."

Health care is one of the biggest tests of her nearly three-year-old tenure. It comes at a time when Pelosi, 69, is widely respected and even feared on Capitol Hill but increasingly unpopular outside Washington. Her statements this spring accusing the CIA of lying to Congress, as well as repeated attacks by Republicans, have hampered her standing nationally. In June, 38 percent of Americans approved of the job she was doing as speaker while 45 percent disapproved, according to a Washington Post-ABC News poll.

"She has become a liability," said Ken Spain, spokesman for the National Republican Campaign Committee. "The speaker's popularity is waning, affecting her ability to legislate within her own caucus. . . . The closer this debate gets to 2010, the likelier it will be that Democrats in tough districts will look to create some separation from their party leadership."

Yet, along the Capitol's marble-floored corridors, hardly any Democrats speak negatively of her. Obama has praised her leadership in steering much of his agenda through Congress, including the economic stimulus package and a controversial climate-change bill.

In testy health-care negotiations over the past month, she has been pragmatic and unusually persistent, according to interviews with more than a dozen House Democrats. "She's like that good coach that knows when to give the pep talk," said Rep. Xavier Becerra (D-Calif.). "And she's clearly raised kids before, because she knows how to mother us along when we're not exactly doing things the way we should."

Pelosi's caucus represents just about every political, regional and ethnic variety, and its members hold wildly divergent views on health care. "She's dealing with 256 Democrats who among them have 450 positions," joked Rep. Peter Welch (D-Vt.). Pelosi respectfully calls her caucus "a great kaleidoscope."

Yet Pelosi, a liberal and the most powerful member of Congress, has remained unquestionably in charge. The woman who Senate Majority Leader Harry M. Reid (D-Nev.) once said presides over the House with an "iron hand" refused to relent on what she considers the bottom line of any bill: a public insurance option. She sternly told lawmakers that health-care reform is "the most important vote you will take in your careers in Congress" and that, above all else, "we have to get this done."

Pelosi regularly kept lawmakers holed up for hours in her conference room just beside the Capitol Rotunda, sweetening the talks with pistachios and Ghirardelli chocolates (the pride of San Francisco). Other times she was less generous. During debate last week over reimbursement rates, participants said, Pelosi threatened to bolt the door and starve lawmakers until they struck a deal. The talks continued until close to midnight.

House Majority Leader Steny H. Hoyer (D-Md.) called Pelosi "the key catalyst" in reaching compromises. "She can be a very tough leader -- very focused, disciplined," he said.

"Nancy knows how to reduce tension in a room," said Rep. Betty McCollum (D-Minn.)."Sometimes she smiles, she makes sure everybody's listened to. When appropriate, she makes a light-hearted comment."

Pelosi has displayed her own frustrations over the slowness of the process. She struggled with getting "everybody singing from the same hymn book and on the same page and in tune," Rep. Elijah E. Cummings (D-Md.) said.

"She's not perfect," Rep. Lois Capps (D-Calif.) said. "She's had moments, but she doesn't lose her cool very often, even if she has a strong, visceral reaction."

Some members of the conservative Blue Dog Coalition have had disagreements with Pelosi and other liberal leaders. Rep. Mike Ross (D-Ark.), lead negotiator for the Blue Dogs, said it was "a mistake" for House leaders to begin writing health-care legislation without them.

But the Blue Dogs have recently been central players, winning concessions last week to allow the legislation to advance from the respective committees. Rep. Baron P. Hill (D-Ind.), a Blue Dog, called Pelosi "gracious," adding: "When things were very tense, she was a speaker of composure."

Although some liberals voiced frustration that Pelosi would compromise with conservatives, most Democrats credit her with striking a deal that enables the full House to take up the legislation upon returning in September. Pelosi frequently bows to the desires of more moderate Democrats, whom she calls her "majority-makers," considering that the electoral wins of moderates in the Midwest and South helped Democrats win control of Congress in 2006.

Rep. Chris Van Hollen (Md.), chairman of the Democratic Congressional Campaign Committee, said appeasing both liberal and conservative Democrats is "the political high-wire act of the new century.

"If you step a little to the left, you fall. If you step a little to the right, you fall. You need to find that balance point in the caucus, and it's remarkable that she's found it," he said.

Pelosi has also inspired lawmakers with what some described as unusually emotional pleas in private discussions for health-care reform. In one meeting, she told fellow Democrats: "This is our time to do something."

"There's a power when you notice somebody really cares," Cummings said. "She's very sincere, and that's part of the glue."

Under siege in recent weeks, Pelosi said she finds a certain tranquillity in the health-care fight. She said she found solace in a coffee-table book that contains descriptions of how phrases came into being. The other day, she looked up "Thank you, ma'am," a phrase President Franklin D. Roosevelt often used as a euphemism for setbacks along the way to passing the New Deal.

As Pelosi tells it, the phrase originated with a young man who was courting a young woman. Driving down the road, they hit a bump. She fell toward him, and he exulted, "Thank you, ma'am." So the speaker has taken to calling her bumps on the road "Thank you, ma'ams."

"We'll have a number of 'Thank you, ma'ams' as we go along," Pelosi said. But, she added, "I know that at the end of the day we will have a great bill, and when we bring it to the floor, we will win."

Staff writers Lois Romano and Perry Bacon Jr. and polling analyst Jennifer Agiesta contributed to this report.