California Gov. Jerry Brown is riding high, though not quite as high as a few months ago, and might not have much to worry about if he seeks another term next year, a new Field Poll shows.

The poll found 51 percent of California voters approve of the job Brown is doing while 33 percent disapprove. That's down slightly from a 57 percent approval rating in February, but it's still higher than each of nine earlier Field Poll measures taken since he was elected in 2010.

Democrats approve of Brown's performance 4 to 1 (68 percent to 17 percent), while nonpartisan or third-party voters approve 54 percent to 29 percent. Republicans disagree, with nearly three times as many disapproving (61 percent) as approving (23 percent).

"He's generally in a comfortable position," said poll director Mark DiCamillo, who said February's higher number might have been due to voters feeling good about the budget forecast Brown had just presented. "Now we're sort of back to reality, dealing with problems like the prisons -- that's kind of a no-win situation for the governor."

Brown has struggled against a federal court order requiring California to release nearly 10,000 inmates by the end of this year in order to improve the state's prison conditions.

Brown hasn't announced his candidacy for re-election next year, though he has been raising campaign money; his committee, which had $7.16 million in the bank at the start of 2013, raised at least $2.34 million in June alone.

With the primary less than a year away, this Field Poll found 43 percent of voters are inclined to support Brown for a second term while 38 percent are not and 19 percent say it depends or they're undecided.

"A fair number are on the fence, waiting to see who the alternative will be," DiCamillo said.

That might sound like good news for two well-known Republicans -- former Lt. Gov. Abel Maldonado, of Santa Maria, and Assemblyman Tim Donnelly, of Hesperia -- who have launched campaigns to replace Brown.

But it still looks like an uphill climb for them: Among Democrats, the margin supporting another Brown term is 2½ to 1 (57 percent to 22 percent); he also has support from pluralities of young women, seniors, college graduates, middle-of-the-road voters and those in the Bay Area and Los Angeles.

Those are the segments likeliest to turn out at the polls, DiCamillo noted, while Republicans account for only 29 percent of the state's voters. Candidates like Maldonado and Donnelly would have to appeal strongly to nonpartisan voters and even some Democrats, he said, "and that is going to be a tall order."

Bobby Wilson, 61, is a Republican but said he's inclined to re-elect Brown, because he's making state lawmakers "bite the bullet."

"And he's been doing pretty good on the tax situation," said Wilson, a retired military serviceman from Emeryville.

Brown's office declined to comment on the poll numbers Tuesday.

The Field Poll surveyed random samples of either 841 or 846 California registered voters between June 26 and July 21; the overall margin of error is 3.5 percentage points.

Josh Richman covers politics. Contact him at 510-208-6428. Follow him at Twitter.com/josh_richman. Read the Political Blotter at IBAbuzz.com/politics.