A California ballot initiative that would establish a Louisiana-style “top two” primary system for the state’s nonpresidential elections has created some unorthodox political alliances in the Golden State.

Almost all of the state’s officially recognized political parties are lining up to oppose the November ballot measure, while an equally bipartisan group of prominent consultants, state officials, and political activists is supporting it.

“California voters are going to pass that thing and pass it big,” predicted Ted Costa, the primary architect of last fall’s gubernatorial recall.

The open primary initiative, Proposition 62, would eliminate the closed primary system, allowing voters irrespective of party registration to vote for any state or federal candidate in the primary. The top two votegetters regardless of party would then advance to the general election. (Under Louisiana’s system, all candidates appear on the general election ballot. If no candidate receives a majority of the vote, the two with the most votes proceed to a runoff.)

Proponents argue that a change in the primary system is necessary because California’s gerrymandered Congressional and state legislative districts encourage extremism on both sides of the aisle. Ideological voters typically turn out in higher numbers in primaries, which frequently serve as quasi-general elections. The lack of competitive districts discourages choice and contributes to voter apathy and cynicism, the advocates say.

High-profile supporters of the proposal include state Secretary of Education Richard Riordan, who is a former mayor of Los Angeles; former Clinton White House Chief of Staff Leon Panetta, who also served in the House; and California Controller Steve Westly.

Moreover, Republican Gov. Arnold Schwarzenegger’s political guru Mike Murphy and fundraiser Kristin Hueter are working to pass the measure along with Garry South, the top strategist to former Democratic Gov. Gray Davis. Schwarzenegger, who rode to power last fall in what was arguably the most crowded open primary in history, has remained publicly neutral on the issue.

Should the open primary initiative pass, political observers believe some House Members and state lawmakers could be put in jeopardy.

“I see incumbents as being vulnerable,” said Allan Hoffenblum, publisher of the California Target Book, which handicaps Congressional and legislative races. He added that a “very left-wing Democrat or right-wing Republican in a district that is not really that left or right wing” would be most endangered under the new system, particularly Members in coastal suburban districts.

But opponents of the ballot measure, which include state parties as well as an array of groups ranging from Common Cause to the League of Conservation Voters, argue that the initiative could encourage extremism, citing the rise of David Duke in Louisiana. They also say it would eliminate choice in the general election, potentially depress voter turnout, and render third parties all but extinct.

Some have also charged that the effort is in part motivated by greedy political consultants and embittered former candidates who lost to more ideologically pure primary opponents — Riordan, for one, lost the 2002 GOP gubernatorial primary to a more conservative candidate.

“What we really need in California is a fair redistricting process, not some goofy primary system,” said Rep. Devin Nunes (R). “It’s like trying to cure a symptom of the sickness instead of the sickness.”

Open primary proponents counter that redistricting proposals have failed on numerous occasions, making November’s initiative the best chance of reforming the system.

The ultimate fate of the open primary may not be determined this Election Day, however. Regardless of the results, advocates on both sides of the issue expect lawsuits to follow.

To complicate matters, late last month, state lawmakers rushed through legislation that put a constitutional amendment on the ballot authorizing proceeds from the sale of surplus state property to pay down California’s bond debt. Language in the initiative would also reaffirm the status quo primary system.

Under a scenario in which voters approve both the open primary and status quo initiative, the one with the higher vote prevails.

In recent weeks, Shawn Steel, the immediate past chairman of the state Republican Party, convened a multipartisan group of prominent state Democrats, Libertarians, Greens and others in Los Angeles to strategize about how to defeat the open primary initiative. During the meeting, Steel said the group discussed how each could best reach out to their respective interest groups.

Last week, opponents filed papers to officially create Californians for Election Accountability — No on 62, the chief nonpartisan vehicle to date aimed at raising funds to defeat the “top two” proposal.

While both major parties are adamantly opposed to the initiative, much of the muscle behind the effort to defeat it appears so far to be coming from the right. The state Republican Party has committed $1 million to defeating the measure, said Steel, adding that regular party mailings as well as slate mailings would urge Republicans to vote no on 62.

The California Democratic Party has so far maintained a lower profile on the issue, a factor Chairman Art Torres attributed to a question of “timing,” not commitment.

“We are going to be as supportive as possible,” Torres said, though he added that the attendance of the state Democratic Party secretary and vice chairman at the Los Angeles meeting that Steel convened had not been officially authorized.

However, some sources have suggested that Democrats may be lying low because the powerful Service Employees International Union is reportedly considering supporting the proposal. Nathan Ballard, a spokesman for the California Labor Federation, AFL-CIO, conceded that unions “are not in total agreement” about whether to support or oppose the open primary initiative, but said the federation would reach a consensus by July 14.

In Washington, D.C., the entire Republican and Democratic Golden State Congressional delegations are expected to oppose the initiative, though only Republican Members have met to discuss strategy. Rep. Ed Royce is heading up the effort to organize the GOP Congressional delegation.

Steel, who is planning to convene another meeting of what he has termed “a multipartisan roundtable” in late July, said he expected state Democrats “to match or exceed” the amount the Republican Party would spend to defeat the open primary.

Most polls have shown Prop. 62 passing by wide margins, though a recent poll commissioned by the opponents showed the gap closing to just 5 percent.

Californians for an Open Primary, whose PAC funded the open primary initiative, was formed in April 2003 but grew out of an earlier effort of the same name that backed the successful 1996 initiative to impose an open or “blanket” primary system.

Although the Supreme Court struck down California’s open primary four years ago, several members of the initial drive regrouped and crafted the current initiative following guidelines laid out in the Supreme Court decision, which specified that a nonpartisan open primary, in which the two top votegetters advanced to the general, could pass constitutional muster.

To date, Californians for an Open Primary’s PAC has raised almost $3 million. Donors include Angelo Mozilo, CEO and chairman of Countrywide Financial Corp., who has chipped in $350,000, and Becky Morgan, an ex-state Senator and honorary co-chairwoman of the effort who along with husband Jim Morgan, former CEO of Applied Materials, has donated about $200,000 to the PAC.