Few states are as synonymous with left-wing politics in the United States as California.

On Tuesday, the western state is headed to the polls to vote in primary elections, ahead of November’s midterms. But a quirk in its primary system has made its governor’s race vulnerable to a Republican takeover.

California is only one of two states that have embraced the so-called jungle primary: a system where any voter can vote for any candidate, regardless of party affiliation. The top two contenders advance to the general election.

With 61 gubernatorial candidates on the ballot this year, Democratic support is heavily divided, allowing two Republicans to rank near the top of the field.

Could a Republican succeed outgoing Democrat Gavin Newsom as governor? And who is going to replace former Democratic House Speaker Nancy Pelosi as representative for San Francisco?

Go inside some of California’s top statewide primary races in this brief explainer.

When is the election?

California’s primary is scheduled to take place on June 2.

Mail-in ballots are also sent to every active registered voter, a measure meant to ensure that people who find it difficult to vote in person still have the chance to cast their vote.

To be counted, those ballots must be postmarked on or before Election Day, and they must arrive at a county elections office no later than June 9.

What are some of the races on the ballot?

Aside from the governor’s race, numerous statewide positions are up for grabs, including attorney general, state treasurer and lieutenant governor.

The race to be mayor of Los Angeles, the state’s largest city, is also being closely watched.

No US Senate seat is on the ballot in California this year, but the race for the House of Representatives is set to be critical.

Every two years, House seats across the country are put on the election ballot. There are 435 in total, divided among the states by population.

California, having the most residents of any state, accordingly commands the most House seats, at 52.

Democrats aim to flip control of the House in November’s midterm elections, so Tuesday’s primaries will be critical to setting up the congressional showdown.

How does California’s primary factor into the nationwide redistricting battle?

Tuesday’s primary will be the first time the state uses its new congressional map.

That map is part of a larger battle between Democrats and Republicans for control of the House of Representatives.

Last year, President Donald Trump pressured Republican-led states like Texas to redraw their congressional districts to help elect right-wing candidates.

In response, Governor Newsom championed a ballot initiative, Proposition 50, that required California to redesign its map, too — but in the Democrats’ favour. The new map is skewed to help the left-wing party win five more House seats this November.

What’s the biggest House race to watch?

There are several key House races in the state, but perhaps one of the most symbolic is the race for California’s 11th congressional district, where San Francisco is located.

That’s the area that Democrat Nancy Pelosi currently represents in Congress.

Her decision to retire after four decades marks the end of an influential career that saw Pelosi become the first elected female speaker of the House, a key leadership role.

Pelosi’s impending retirement has kicked off a contentious primary. San Francisco has been a springboard for several top Democratic leaders, and multiple left-wing candidates have thrown their hat into the ring.

The frontrunner is currently state Senator Scott Wiener, a moderate who has campaigned on affordable housing.

But he is facing two progressive challengers. One is Saikat Chakrabarti, a former chief of staff to Representative Alexandria Ocasio-Cortez. The other is Connie Chan, a San Francisco supervisor endorsed by Pelosi.

Are any House races competitive?

Thanks to the redistricting push, Democrats are likely to dominate more House races in California this year.

But there could still be surprises. One of the tightest races is for California’s 22nd district, in the San Joaquin Valley.

Republican David Valadao has represented the region since 2013, but he is facing heat from two Democrats: centrist Jasmeet Bains and progressive Randy Villegas.

The Los Angeles Times has described the primary as a “bitter slugfest” between the two Democrats, each of whom is hoping to face Valadao in November’s midterms.

Why is there so much attention on the governor’s race?

Newsom has become a national figure during his two terms as California’s governor, serving as a frequent sparring partner for President Trump. He has even been floated as a potential 2028 presidential contender.

But term limits make Newsom ineligible for re-election. His open seat is one of the hottest races this primary season.

No candidate has emerged as a clear frontrunner in the governor’s race, adding to the speculation about its outcome. California has not elected a Republican governor since 2006.

The race has also seen bouts of scandal. Former Democratic Representative Eric Swalwell, previously considered the frontrunner, dropped out of the race in April following reports of sexual misconduct.

What is a jungle primary?

The term “jungle primary” can have different meanings, but it is commonly used to refer to California’s top-two primary system.

The concept is simple but controversial. Voters can pick any candidate, regardless of party. The top two vote-getters advance to the general election.

The idea was to encourage the participation of independent candidates and voters. But this year, a dilemma has arisen.

In the governor’s race, the Democratic field is so wide and so divided that no left-wing candidate might progress to the general election, despite California being a heavily Democratic state.

That opens a path for the two Republican frontrunners — Chad Bianco and Steve Hilton — to win the primary and lock the Democratic Party out of the gubernatorial race in November.

Who are the leading Republican candidates?

Hilton and Bianco, the top Republican contenders, have both campaigned on the premise that California has been set back by years of Democratic leadership.

Steve Hilton, a Fox News commentator, has received President Trump’s endorsement.

An immigrant from the United Kingdom, Hilton has campaigned heavily on affordability, proposing to end the state income tax for the first $100,000 residents earn. He also proposed increasing California’s oil production and cutting government bureaucracy.

He has also voiced support for an investigation into claims of voter fraud, falsely pushed by Trump following his loss in the 2020 presidential election.

Riverside County Sheriff Chad Bianco has likewise allied himself with Trump’s platform.

Bianco has run on a law-and-order platform, pledging to roll back criminal justice reforms and “sanctuary” laws that limit collaboration with federal immigration enforcement.

The sheriff faced legal challenges this year after he seized 65,000 ballots as part of what he called a “fact-finding mission” into possible election fraud, mirroring Trump’s rhetoric about “rigged” votes.

Who are the top Democrats in the race for governor?

Democrat Xavier Becerra, who served as a cabinet member under former President Joe Biden, has emerged as a late-season frontrunner.

Most recently the secretary for the US Health and Human Services Department, Becerra has spent decades in politics. He served as California’s attorney general from 2017 to 2021 and was a member of Congress before that.

But his opponents have questioned his leadership after his former chief deputy was involved in an alleged fraud scheme. Becerra himself is not accused of wrongdoing.

Running to Becerra’s left is billionaire hedge fund manager Tom Steyer, who has used his fortune to fund activism around issues such as climate change.

If elected, he has pledged to increase taxes on corporations, lower energy costs, and ban corporate contributions to political action committees (PACs) in state elections.

But Steyer has faced criticism over past investments in mining and private prison companies.

Other leading Democrats in the race include San Jose Mayor Matt Mahan and former Representative Katie Porter.

What do the polls say about the governor’s race?

While some polls earlier this year showed Hilton and Bianco leading the race, Democrats have surged back to the forefront.

A Public Policy Institute of California survey released on May 28 shows Becerra with 23 percent support, closely followed by Hilton with 20 percent and Steyer with 15.