An independent California commission has set the stage for what could be the largest shake-up of the state's political system in decades – and potentially give Democrats a two-thirds majority in both houses of the Legislature.

Ending weeks of public hearings involving hundreds of public comments, the California Citizens Redistricting Commission put finishing touches Sunday night on 177 new legislative, congressional and Board of Equalization districts.

The 14-member panel, scheduled to take a tentative vote Friday, was created by voter passage of Proposition 11 in 2008 to strip legislators of the right to draw their own districts. Its duties were expanded to include congressional maps last year.

California Republican Party Chairman Tom Del Beccaro was laying the groundwork Monday to fight some or all of the maps, saying attorneys were considering either a lawsuit or a referendum that would place the issue before voters.

Asked if the commission's final product would give Democrats a two-thirds majority in the Legislature, Del Beccaro said simply, "I think it has raised the stakes for that considerably."

Other issues decided by the commission of five Democrats, five Republicans, and four independent or minor-party voters included:

• About a dozen of the legislative districts encompass the homes of two incumbents, raising the possibility of showdowns.

In the Sacramento area, incumbents drawn into the same district include Assembly Democrats Roger Dickinson and Richard Pan of Sacramento; Assembly Democrat Alyson Huber of El Dorado Hills and Republican Beth Gaines of Roseville; and state GOP Sens. Ted Gaines of Roseville and Doug LaMalfa of Richvale.

• Draft maps pairing Sacramento and Davis in Senate and Assembly districts were dumped, guaranteeing that the two will continue to have separate legislators.

• Sacramento County remains targeted for six Senate districts, with its central city preserved but its suburbs split multiple ways.

• Sacramento International Airport will remain in the same congressional district as much of Sacramento city.

The commission's decisions are expected to be final, but they are not barred by law from changing them this week.

Three redistricting experts interviewed Monday by The Bee had differing views on how many seats would be at risk of changing party hands under the new maps, but all agreed that Republicans would be hard-pressed not to lose ground.

Some projections had Democrats gaining up to four seats in the congressional delegation and two, perhaps three, in the state Senate.

Tossups could swing the margin a little either way, but none of the analysts thought it likely that Democrats would lose ground in the congressional delegation, currently a 34-19 split, or the state Senate, now 25-15.

In the Assembly, there were more swing districts, about a half-dozen, and less certainty for gains by either party. Republicans could hold the current partisan line, 52-28, or either party could add or lose a seat, analysts said.

"I don't think it's likely that (Democrats) are going to get two-thirds in the Assembly," said Paul Mitchell of Redistricting Partners.

Tax measures cannot be passed in California without a two-thirds majority vote in the Assembly and Senate, so that threshold has long been coveted by Democrats, who are two seats shy in each house.

Del Beccaro said that he is particularly upset with the new state Senate maps, which appear to place in jeopardy two seats currently held by Republicans – Tony Strickland of Moorpark, and Sam Blakeslee of San Luis Obispo.

"If I were a Republican in the state Senate, I'd be looking at this as a disaster," said Tony Quinn, a former legislative staffer involved in redistricting issues.

The new maps also could make it difficult for the GOP to count, in years to come, on the seat held by Sen. Anthony Cannella of Ceres, analysts said.

The GOP potentially could snatch the Orange County seat of Sen. Lou Correa, a Santa Ana Democrat who is termed out in 2014, analysts noted.

GOP consultant Matt Rexroad was not willing to concede that Republicans would lose ground in the Senate.

"Republicans could end up with anywhere from 12 to 15 members," he said.

California's political shake-up is likely to be affected by the fact that nearly three dozen new legislative districts have no incumbent living in them.

In Congress, more than 30 incumbents are 60 or older.

Balloting also will be rocked by implementation of a voter-approved ballot measure calling for the top two vote-getters in primary elections, regardless of party, to square off in general elections. Showdowns between candidates of the same party are likely.

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Call Jim Sanders, Bee Capitol Bureau, (916) 326-5538.

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