Sen. Hillary Rodham Clinton's robust 25-point lead over Sen. Barack Obama in California has shrunk by nearly half since October - but state Democratic voters by a 3-1 ratio still believe the New York senator has the best chance of winning the presidency, a new Field Poll shows.

With just seven weeks until the state's Feb. 5 presidential primary, the latest statewide poll shows that 1 in 5 Democrats is undecided - a number that has nearly doubled since early last year.

Among the poll's key findings:

Both Clinton and Obama enjoy high favorable ratings among Democrats, but Clinton leads 2-1 among women and Latinos while Obama has a far more positive image among independent and African American voters.

"There's no significant surge for Obama, it's just greater hesitancy amongst those who were formerly supporting Clinton," said Field Poll director Mark DiCamillo. But California Democrats are "not really moving to any one candidate, mainly going into the undecided column."

Clinton has stronger support as a nominee among her party's voters. And by a sizable margin, Democratic primary voters also say Clinton has the best chance of being elected president if she becomes the nominee.

Clinton maintains strong leads in key geographic regions - Los Angeles County and the San Francisco Bay Area - and is stronger with voters in every age group.

Obama gets more crossover support from Republicans - 47 percent say they would consider supporting him, versus just 20 percent who would support Clinton.

That suggests that in the general election, "Obama might stand a better chance," said DiCamillo. But he cautioned that "Republicans in this state generally get behind the Republican nominee" and that expressed support "might not hold" in a general election.

While former North Carolina Sen. John Edwards' support has remained stable in California, there is speculation about how Democratic voters in California would be swayed if he doesn't do well in the first crucial states of Iowa and New Hampshire. Second choice preferences among his supporters show Edwards' voters "would be more inclined to support Obama than Clinton, which could make the race in California closer," the survey shows.

The latest Field Poll is based on 1,283 registered voters in California - 543 Democrats, 439 Republicans and 301 independent or "decline to state" voters. Democratic primary preferences were based on 457 voters likely to vote in the Feb. 5 primary. The margin of error for the survey of likely Democratic voters is plus or minus 4.7 percentage points.

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