Voters went to the polls in California on Tuesday to decide whether to oust the Democratic governor of the most-populous US state or have him serve out the remaining 16 months of his term.

Gavin Newsom, 53, who was elected in a landslide in November 2018, is widely expected to survive the quirky recall election, fending off a field of 46 challengers, mostly Republicans.

US President Joe Biden is stumping for California Governor Gavin Newsom on the eve of a recall vote
US President Joe Biden is stumping for California Governor Gavin Newsom on the eve of a recall vote AFP / Brendan Smialowski

Polls opened at 7:00 am Pacific time (1400 GMT) in the Golden State, which boasts the world's fifth biggest economy, and are to close at 8:00 pm.

Many Californians have opted to vote by mail and they have until Tuesday evening to return a ballot on which they are asked firstly if they should fire Newsom, and secondly who should replace him.

Gavin Newsom needs a simple majority to keep his job, and render the ballot's second part irrelevant
Gavin Newsom needs a simple majority to keep his job, and render the ballot's second part irrelevant AFP / Brendan Smialowski

To remain in office, Newsom needs to win more than 50 percent of the vote. If he fails to reach that threshold, the candidate with the next highest vote total becomes governor -- no matter small the number.

After a shaky start, the telegenic Newsom, a former mayor of San Francisco, looks set to survive the recall. Poll-crunching website fivethirtyeight.com predicted on Tuesday that 57.3 percent will vote to keep him.

President Joe Biden flew to California on Monday to lend his support to his fellow Democrat and warned voters they risk a Donald Trump-style governor if they remove Newsom.

Newsom's main challenger is Larry Elder, a right-wing talk radio star who has openly supported controversial former president Donald Trump
Newsom's main challenger is Larry Elder, a right-wing talk radio star who has openly supported controversial former president Donald Trump AFP / Frederic J. BROWN

"You either keep Gavin Newsom as your governor or you get Donald Trump," Biden told an audience in Long Beach. "Voting no will be protecting California from Trump.

"The choice should be absolutely clear."

President Joe Biden flew to California to lend his support to Governor Gavin Newsom, who is facing a recall election
President Joe Biden flew to California to lend his support to Governor Gavin Newsom, who is facing a recall election AFP / Brendan Smialowski

Newsom also raised the spectre of the former Republican president, a figure widely loathed in California, where registered Democrats outnumber registered Republicans by two to one.

"Trumpism is still on the ballot in California," he said.

Newsom's main challenger is Larry Elder, 69, a right-wing talk radio star who has openly supported Trump.

California Governor Gavin Newsom needs 50 percent of the vote to survive the recall effort
California Governor Gavin Newsom needs 50 percent of the vote to survive the recall effort AFP / Brendan Smialowski

The Black ex-lawyer is polling atop a field of hopefuls which includes a cannabis consultant, a former San Diego mayor, reality TV star Caitlyn Jenner and a self-proclaimed "Billboard Queen."

Also on the ballot is former Republican gubernatorial candidate John Cox, who won just 38 percent of the vote in 2018 to Newsom's 62 percent.

SOUNDBITES
SOUNDBITES DC POOL / Sébastien VUAGNAT

The recall initiative, which has cost the state some $280 million, was sparked by Republicans angry over mask mandates and Covid lockdowns.

Republicans were upset by Newsom's lockdown rules they say unnecessarily kept children out of school and suffocated small businesses as the coronavirus killed thousands in the state.

Democrats complain that the Republican-led recall is an attempt to hijack the state's government; seizing power in extraordinary circumstances when they could never do it in a regular poll.

Although Newsom won handily in 2018, California's electoral rules set the bar low for getting a recall up and running.

Malcontents need only gather signatures equivalent to 12 percent of the number of people who voted in the last election -- in this case, that figure was 1.5 million.

California's population is around 40 million.

The recall is only the second in California's history; the first brought bodybuilder-turned-actor Arnold Schwarzenegger to office in 2003.

"The Governator," who ended up running the state for more than seven years, was California's last Republican chief executive.

The petition to remove Newsom gathered steam after he was snapped having dinner at a swanky restaurant, seemingly in breach of his own Covid rules.

That fuelled a perception he was an out-of-touch hypocrite.

Biden's stop in Los Angeles came at the end of a day when he swung through the western United States on a tour aimed at highlighting the dangers of climate change.

Millions of acres (thousands of square kilometers) have already burned, with many months left to run in the fire season.