There had, until now, been a note of uncertainty about why beach owner Vinod Khosla decided to kick people off Martins Beach, but the billionaire venture capitalist made his motives pretty clear, according to this Chronicle story by Melody Gutierrez.

The green tech titan does not want the hoi polloi touching what he believes is his sand, tidelands or surf.

“Martin’s beach is private property, including the sandy beach and the submerged tidelands seaward of the mean high tide,” argued lobbyists hired by Khosla in a letter to state lawmakers. “There are no existing ‘public’ lands to which access is needed.”

The techie tycoon’s hired guns were trying to convince lawmakers to vote against a bill by Sen. Jerry Hill, D-San Mateo requiring the State Lands Commission to buy the road or obtain access rights to Martins Beach, 6 miles south of Half Moon Bay. The Senate passed the bill 22 to 11 Wednesday. It will now be taken up by the Assembly.

The lobbyists for Khosla are using as justification for their position a decision last October by Superior Court Judge Gerald Buchwald that said Martins Beach was still subject to the Treaty of Guadalupe Hidalgo, which ended the Mexican-American War in 1848. The treaty essentially required the United States to recognize Mexican land grants as long as the owner filed a claim. Jose Antonio Alviso, who owned the land grant at the time, filed such a claim, and a patent for the beachfront property was issued in 1865.

Judge Buchwald ruled that Alviso’s patent, handed down over the generations, extinguished all public rights to the property, including beach access rights established under the public trust doctrine in the California Constitution, which was first drafted in 1879.

The letter opposing SB968 claimed that Buchwald’s order means Khosla does not have to provide access to either the beach or off-shore submerged tidelands, which his lawyers point out were specifically mentioned in Buchwald’s ruling.

Lawyers fighting for public access to the beach were apoplectic.

“It’s preposterous,” said Joe Cotchett, the lead attorney for Surfrider, which is awaiting a decision on a lawsuit claiming that Khosla needed a California Coastal Commission permit before he could close the road or make other improvements.

Gary Redenbacher, who argued the case before Judge Buchwald, said even under Mexican law beaches were public property below the highest tide line.

“The beach itself has always been public,” he wrote in an e-mail. “Therefore, the claim by the lobbyists that it is a private beach has zero credibility in the law whether part of a Mexican Land Grant or not.”

There has been speculation that Khosla’s real motive in the beach battle is to extract payment for a public easement and to force the government to absolve him of liability concerns and take over responsibility for public safety and security. His latest actions, opponents say, lay waste to that theory.

“This,” Redenbacher said, ” is a blatant attempt by Khosla to abscond with public property.”