It's more likely to rain in Death Valley on any given day than it is for a California legislator to vote in opposition to the majority of his or her party on any given bill, a new Bee analysis shows.

This tendency is exposed most prominently during the annual budget ritual, when Democrats and Republicans hunker down as another busted budget deadline fades into the past and the state teeters without a spending plan.

But their us-and-them routine is carefully honed throughout the year, according to the analysis, based on newly available Legislative Counsel data showing every vote cast by every legislator this session through September.

On average, individual Democrats in the California Legislature voted with the majority of their party or abstained 99 times out of 100 this session. Republicans, on average, voted with the majority of their party or abstained 96 out of every 100 times.

"California is by far the most polarized state legislature" in the nation, said professor Boris Shor, with the University of Chicago's Harris School of Public Policy Studies, who recently published a study on the ideological composition of legislatures. "California makes the U.S. Congress look like tiddlywinks."

That polarization is increasing, Shor said, a statement borne out by the fact that during the 1970s, '80s and early '90s, California legislators agreed on budgets at a speed their successors can only envy.

Legislators often talk of striving for bipartisanship, but The Bee found those promises rarely translate into voting with the opposing party when the majority of Democrats go one way and the majority of Republicans another. For example:

• Last October, Senate Democrat Lois Wolk of Davis ran campaign ads touting her independence. She talked about how Republican Gov. Arnold Schwarzenegger often signs her bills and told The Bee, "I crossed the aisle from the beginning."

So far, in contested floor votes this session, however, Wolk shunned her party just 14 times – about 2 percent of 562 votes.

• After winning his seat last November, Assembly Democrat Bob Blumenfield's campaign posted a statement online saying, "Bob is off to a great start to form bipartisan coalitions that will support reform measures in Sacramento and bring positive change to the district."

In contested floor votes, Blumenfield, of Woodland Hills, voted against his party just four times – less than 1 percent of 657 votes.

• In a posting on his Web site earlier this month noting that many of his bills become law, Assembly Republican Kevin Jeffries of Lake Elsinore told his constituents, "Focusing on issues such as water, transportation, emergency response and other issues brought to me by my constituents avoids many of the partisan pitfalls that so many Republican bills fall victim to."

In this session's contested votes, Jeffries sided with Democrats only 25 times – about 4 percent of his votes.

Dozens of other legislators voted against their parties even less often.

Explaining her record, Wolk said she has opposed the party line on key issues this session, such as borrowing local funds to balance the state budget and the water package being debated. She also noted that many of her bills have had Republican support.

"I'm a traditional Democrat and most of my votes are consistent with the principles of the Democratic Party, but that's not the end of the story," she said. "On top policy issues, I've voted differently from my party and according to my best judgment."

Defenders of party unity say legislators tend to vote alike out of a deep belief that the other side is wrong. Alberto Torrico, the second-highest ranking Democrat in the Assembly, said most of his party's constituents would not be happy to see their leaders neglecting core principles for the sake of cooperation.

"It's very important for us to vote in a way that demonstrates the differences between parties," he said. "When it comes to fundamental differences, it's pretty easy."

Call The Bee's Phillip Reese, (916) 321-1137.