LOS ANGELES - Television's highest-earning actress and a San Francisco art museum chief are two of the key figures in the bid to establish a new museum on the National Mall in Washington devoted to the history and culture of American Latinos.

But Eva Longoria, who will rally public support for a bill in Congress to create the museum, and Jonathan Yorba, chairman of the museum-lobbying group that picked her, also played key roles in the creation of a problem-plagued Los Angeles museum and cultural center focused on the contributions of Mexican Americans in Southern California.

From 2004 to 2006, Yorba was the first executive director of La Plaza de Cultura y Artes, trying to lay the groundwork for the downtown museum that finally opened in April and almost immediately ran into extreme financial difficulties.

At La Plaza, Yorba was expected to help ignite a $50 million fund-raising effort, but it never got off the ground. The organization raised just $51,000 in private donations during the two years he was in charge; he was paid $210,000 over the two years, according to the nonprofit La Plaza's federal tax returns.

Longoria, who according to Forbes magazine earned $13 million acting in Desperate Housewives and doing product endorsements during the 12 months ending last May, has served on the financially strapped La Plaza's board for the last 18 months. The board learned three months after its opening that La Plaza was in financial turmoil. Half its staff was laid off amid assertions by the board that chief executive Miguel Angel Corzo had mismanaged La Plaza's business affairs. Corzo left after his contract ran out in August.

Yorba is now chairman of Friends of the National Museum of the American Latino, a private, nonprofit group that's pushing for creation of a museum that, according to current projections, would require the federal government to pay half its $402 million construction cost and about 40 percent of its $47 million annual operating cost.

The Friends group announced Dec. 8 that Longoria and Emilio Estefan, the Miami-based musician and record producer who was instrumental in launching his wife, Gloria, to pop stardom, "have agreed to take leadership roles" in the campaign to win congressional approval.

Last month, identical bills were introduced in the House and Senate that would create the Latino museum as a new branch of the Smithsonian Institution. The bills, sponsored by nine senators and two House members, among them four Latinos, call for establishing the museum in the Arts and Industries Building, a vacant, 130-year-old historic structure on the National Mall.

In September 2004, La Plaza, whose prime mover is Los Angeles County Supervisor Gloria Molina, received from the Board of Supervisors what backers of the national Latino museum are seeking from Congress - a green light to create an institution, a commitment of construction money, and authorization to renovate two historic, county-owned buildings from the 1880s.

At the time, Yorba said he was going to "hit the fund-raising trail" to help La Plaza reach its goal of raising $50 million in three years. As it turned out, over the next seven years, La Plaza managed to raise only about $2.9 million in private donations; government expenditures have totaled $36 million.

The lack of donations has been the primary cause of La Plaza's woes. Private funds are expected to cover its staffing and programming costs; the county provides $1 million annually for maintenance, insurance, and utilities.

Now Yorba, whose day job is chief executive of the Mexican Museum in San Francisco, is the volunteer chairman of Friends of the National Museum of the American Latino, making him an important player in the lobbying effort to pass the legislation that would create it. The position does not mean he would help run the museum if it is approved. In addition to lobbying for the museum bill, the Friends group is trying to raise money for the project. However, a preliminary federal report on the museum says that an official fund-raising campaign - projected to take 10 years - would not begin until Congress authorizes its creation.