From the Sunlight Foundation:

Longtime Democratic lawmaker Maxine Waters has perfected an unusual tactic for fundraising over the years – getting candidates, including some of California’s most prominent political figures, running for state and local offices, to pay as much as $45,000 for her endorsement on election mailers. In this election cycle alone, Waters has raised 59 percent of her campaign’s treasury through these “slate mailers.”

…State assembly candidates, judges, Los Angeles city council members and city attorneys, school board members and insurance commissioner hopefuls have all paid Waters’ campaign to appear on her slate mailers, often far in excess of the amount a political committee could legally contribute to a congressional campaign. In all, Waters has endorsed 46 candidates and ballot measures while collecting fees. She lends her opinion on five candidates and five measures free of charge.

h/t Mickey Kaus’ twitter feed.