Waters, 66, was one of 13 children born to a single mother in St. Louis. She moved to Los Angeles as a young woman, taking jobs in a garment factory, as a telephone operator, as a Head Start teacher and then as a staff member for former City Councilman David Cunningham.
In 1976, she was elected to her first political office, the Assembly, and rose to become part of Speaker Willie Brown's Democratic leadership. Among her crowning accomplishments was legislation requiring state pension funds to divest in South Africa, then under apartheid.
She also became a skilled street organizer, feared and admired for her ability to rally crowds around causes. She has led demonstrations protesting U.S. policy in Haiti, police brutality, alleged CIA complicity in the spread of crack cocaine, and attempts to restrict abortion rights, among others.
In 1990, she won a seat in Congress, and she has repeatedly been reelected with about 80% of the vote. Her district includes Inglewood, Hawthorne, Gardena, Lawndale and portions of the city of Los Angeles.
After riots devastated Waters' district in 1992 -- her local office was burned down -- she showed up uninvited to a White House summit between then-President Bush and congressional leaders. Later that year, she won $10 billion in additional funds for cities from the Democratic-controlled Congress.
Back home, Richard Riordan was running for mayor. Although she could not bring herself to endorse the rich Republican, she agreed not to endorse his opponent, Mike Woo, a liberal Democrat. The Riordan camp viewed her neutrality as a big help, sources said, and his administration paid her back by appointing her friends to powerful posts.
With her power now reduced in a Republican-controlled Congress, she has worked closely with the Republican chairman of the housing subcommittee, where she is the ranking member. U.S. Rep. Robert Ney of Ohio said their cooperation "has shocked a lot of people" and resulted in 11 bills being passed out of the subcommittee. He described Waters as knowledgeable, reasonable and direct.
Yet she still moves easily from the House floor to the streets of Los Angeles. Last month, she led 1,000 people at a protest in Willowbrook over county plans to close the trauma center at Martin Luther King Jr./Drew Medical Center.
It is Waters' ability to rally voters in South Los Angeles that has become her stock in trade. Political novices and heavyweights alike vie for her endorsement. Those who win it sometimes get a call or a visit from more than one of her family members.
A few years after Waters endorsed a bond issue for schools in her congressional district, she endorsed the Inglewood school board members who would administer it. While running for election, they paid the slate mailer run by Waters' daughter to publicize her support.
Then her husband went to work. He collected $54,000 from a bond underwriting firm for helping win the school board business.
There has been no more direct tie between Waters' political influence and her family's fortunes than L.A. Vote.
The political organization for years has published the slate mailer, a ballot look-alike featuring a photo of Waters mailed to homes in South Los Angeles with a check mark next to candidates she has endorsed.
A check mark has meant thousands of votes from Waters' loyalists, political consultants say.
Slate mailers like Waters' are a California tradition. They flourish in population centers like greater Los Angeles, where they allow local candidates to share the cost of mass mailings that target blocs of voters for a fraction of the amount charged by broadcast outlets and daily newspapers.
To guarantee themselves a spot on Waters' sample ballot, candidates have had to jump through two hoops. First, they had to get her endorsement, candidates say. Then, they say, they received a call from Karen Waters telling them the cost of advertising it. Karen said she decides on the fee without consulting her mother.
Campaign disclosure reports show that L.A. Vote has collected more than $1.7 million over the last eight years, mostly from candidates and ballot measure sponsors who paid to have their names and causes listed. About $450,000 went to Karen Waters and her consulting firm, Progressive Connections, and $115,000 to her brother, Edward, a high school basketball coach and sometime political consultant.
Payments from campaigns have varied widely. The state law that governs slate mailers sets no limits on how much candidates can be charged or how much people like the Waters children can be paid. It requires only a public accounting.
Well-known politicians such as former Gov. Gray Davis, state Treasurer Philip Angelides and Los Angeles Mayor James K. Hahn have been charged tens of thousands of dollars. Others have paid nothing. A school board candidate paid $250. Al Checchi, a wealthy businessman and political novice who ran for governor in 1998, paid L.A. Vote the most: $171,000.