From the article "Latino Groups Play Key Role on Hill/Virtual Veto Power in Immigration Debate" (link):

When Sen. Edward M. Kennedy (D-Mass.) declared last week that unnamed "stakeholders" would decide whether Congress overhauls immigration law this year, Latino organizations in Washington understood exactly what he meant.

After laboring in obscurity for decades, groups such as the National Council of La Raza, the Mexican American Legal Defense and Educational Fund, and the National Immigration Forum are virtually being granted veto power over perhaps the biggest domestic issue coming before Congress this year. Organizations that represent what is now the nation's largest minority group are beginning to achieve power commensurate with their numbers.

The NCLR (the LR part means "The Race") has links to and funds extremists. MALDEF has at least an indirect link to the Mexican government.

...Such groups were practically in the room yesterday, maintaining contact as Democratic and Republican senators tried to hammer out a new immigration bill...

...A deal on ["guests" and family reunification] could depend on the assent of Kennedy's "stakeholders," Democratic negotiators agreed...

They go on to quote William Ramos from the National Association of Latino Elected and Appointed Officials (NALEO has a direct link to the Mexican government) and Brent Wilkes of LULAC (League of United Latin American Citizens).

...LULAC, MALDEF, La Raza and the National Immigration Forum are part of a broad network of immigrant rights groups that hold nightly conference calls and strategy sessions on the legislation. The groups speak daily with top aides in Reid's and Kennedy's offices.

...The White House held a meeting 2 1/2 weeks ago with Latino advocates, labor unions and civil rights organizations in which an adviser outlined an administration's policy based on increased border security and a temporary-worker program. Homeland Security Secretary Michael Chertoff and Commerce Secretary Carlos M. Gutierrez have also met with some of the groups.

..."Power is not handed over. To get your place at the table, you have to fight for it," Wilkes said.