Even as the state Senate voted last week to approve California's $68 billion high-speed rail plan, opponents pressed forward on a Kings County lawsuit to stop the controversial construction project.

Former California High-Speed Rail Authority Chairman Quentin Kopp, who led a 20-year fight for the bullet train, said he believes this latest lawsuit poses a real threat.

The compromise high-speed rail plan crafted by Gov. Jerry Brown and approved Friday is a "mangled" -- and probably illegal -- version of the project state voters enacted in a 2008 initiative, Kopp said.

"They have distorted high-speed rail and twisted it into (providing) money for commuter rail services," he said.

Kopp is not a party to the suit but said he was familiar with its assertions. His comments are of note because for decades -- first as a San Francisco legislator and then as rail authority chairman -- he was among California's leading advocates for high-speed rail.

"I can't say it was unnecessary to get the votes, but it's not high-speed rail," Kopp, who also is a retired judge, said of the compromise plan. "It violates (the initiative) in at last four respects and maybe five."

In a statement, rail authority CEO Jeff Morales said the rail plan enacted last week -- including its expenditures on commuter rail service in the Bay Area and Southern California -- was "fully in compliance" with the bullet train law enacted by voters, called Proposition 1A.

"This is now a truly statewide vision that is born directly from the funds made available when the voters passed Prop. 1A," he said of the new rail plan.

Morales declined to comment on the lawsuit filed in Sacramento County Superior Court by the Kings County Board of Supervisors and residents John Tos and Aaron Fukuda. Central Valley farmers fear that rail construction will wreck vast stretches of prime agricultural land.

Tos is a farmer who owns walnut orchards that are in the path of the proposed high-speed train route through the county. Fukuda and his neighbors in the Ponderosa neighborhood east of Hanford also would be displaced by one of the route options.

The suit itself is not new. It was originally filed in November, and Friday's filing represents the second time the complaint has been changed by Redwood City attorney Michael Brady.

A Sacramento judge ruled on June 15 that the suit, as then drawn up, failed to demonstrate that approval or expenditure of funds was imminent, but the court's ruling gave Brady until last Friday to amend the complaint.

The suit accuses the state of illegally spending public funds on the bullet train, arguing that Brown's reconfigured or "blended" plan for the rail system simply cannot produce what voters authorized.

On four earlier occasions, judges have rebuffed similar lawsuits, saying they were filed prematurely. That might no longer be the case now that the Legislature has voted to issue $4.5 billion in state bonds to begin construction of the first segment, a line between Merced and Fresno.

Michael Brady, Kings County's lawyer, said he was in the Capitol on Friday to watch the Senate vote. As approval neared, he said he went to the courthouse and filed the lawsuit, which seeks a court order stopping all spending on the project.

"The vote by the Senate doesn't make any difference," he contended. "The Legislature cannot approve a project that violates the law passed by the voters."

The system approved by voters in 2008 is supposed to link San Francisco and Los Angeles with electric trains traveling more than 200 mph, whisking travelers between the two cities in two hours, 40 minutes.