California has moved its presidential primary up from June to March, which could prove to be one of the most decisive factors in the 2020 election.

Historically, early primary states have had a huge say in the presidential nominees for both major parties so candidates focused much of their energy on campaigning there.

In the past, California's late primary meant voters in the country's most populous state didn't have much of an influence on the presidential nominating process.

California's secretary of state said the earlier primary is already driving candidates to shift focus toward the West.

California sends more delegates to vote in the presidential nominating process at the Democratic National Convention than any other state, so the early primary means candidates can't afford to ignore it.

One of the biggest moments in the 2020 presidential election may have happened back in September 2017.

That's when then-Governor Jerry Brown of California signed legislation permanently moving the state's presidential primary from June to March.

The move was designed to give a state that's home to nearly 40 million people a far greater role in the presidential nomination process, and it could have a major affect on where and how candidates focus their energy not only in 2020 but all future presidential elections.

California Secretary State Alex Padilla said that early primary states are "always meaningful as a sort of test for presidential candidates" and he feels strongly that by moving up its presidential primary his state has sent a clear message to candidates that "if you want to be an effective leader of the United States you can't do so without respecting California."

California Secretary of State Alex Padilla. Justin Sullivan/Getty Images

'An early primary will allow California voters to have a significant say'

"California is the most populous state in the nation, we're the most diverse state in the nation, we represent the largest economy of any state in the nation by far, and an early primary will allow California voters to have a significant say in determining nominees for president of the United States," Padilla told INSIDER.

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By the time California's primary took place in June 2016, there was virtually no doubt that Donald Trump would be the GOP presidential nominee. It was also becoming quite clear that Hillary Clinton would ultimately defeat Bernie Sanders in their heated battle for the Democratic nomination.

This is precisely why California decided to move the primary up to March 3, or Super Tuesday, the day most states traditionally hold their primaries after the early nominating contests in Iowa, New Hampshire, Nevada and South Carolina.

'A political world unto itself'

History tells us that early primary states are extremely important for anyone vying for the nominations of both major parties. With the exception of former President Bill Clinton in 1992, in the past four decades no candidate was won the Republican or Democratic nomination without winning either Iowa or New Hampshire.

In 2020, California could be just as decisive for Democrats as these two states.

California is far more representative of the overall US population than states like Iowa and New Hampshire, which are both small and overwhelmingly white.

Moreover, California sends more delegates to vote in presidential nominating process at the Democratic National Convention than any other state. There are nearly 500 delegates up for grabs in the western state. Comparatively, other large states like Florida and New York both have fewer than 300 total delegates.

As Padilla put it, "California, by virtue of its size and the number of voters here is almost a political world unto itself in the national political map."

Los Angeles, California Getty Images

Accordingly, California leaders hope that moving the primary up will pressure candidates to pay more attention to the western state and its voters, given presidential hopefuls have typically dedicated much of their energy to gaining a lead via early primary states — particularly Iowa and New Hampshire.

"Candidates for president are not strangers to California; they're not shy about coming to California to raise money," Padilla said. "Voting early in the primary season will force candidates for president to have to come earn California votes, not just ask for contributions."

"We're looking forward to that engagement between candidates and voters ... in a way that hasn't been done in the past," Padilla added.

Supporters cheer while listening to Sen. Kamala Harris speak at the launch of her campaign for President of the United States at a rally at Frank H. Ogawa Plaza in her hometown of Oakland, California, U.S., January 27, 2019. Elijah Nouvelage/Reuters

The 'California bump'

California voters will also be able to begin sending mail-in ballots on February 3 — a month before the primary — which is the same day as the Iowa caucus.

Padilla said there's "no doubt" there will be an increase in voter turnout next March after a historic number of Californians headed to the polls in November's midterm elections.

The early primary date and flexible voting options in the delegate-rich state could see candidates place more stock in focusing on issues that voters in California care about, such as immigration and climate change.

Demonstrators protest in front of the Metropolitan Detention Center, Federal Bureau of Prisons, during a national day of action called "Keep Families Together" against the Trump administration's 'Zero Tolerance' policy in Los Angeles, California, U.S. June 30, 2018. Monica Almeida/Reuters

"Every race is a little bit different," Padilla said. "Just as candidates for president look for either an Iowa bump or a New Hampshire bump, they're going to be equally looking for a California bump in momentum. That's great for California voters and the issues that matter to us."

Candidates are already shifting focus to the West

California is an expensive state in which to campaign, so candidates with larger pockets are more likely to focus energy there. The fact that it's so much bigger than other states also means candidates have a much broader audience to appeal to, which can prove challenging.

Padilla, who's also a former state senator with roughly two decades of experience in California politics, said he's already seen a shift in behavior from candidates as a result of the earlier primary date.

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He said several Democratic candidates have "had higher profile events or or speaking opportunities in state, whether they been declared candidates or rumored to soon be declared candidates."

"You do hear the chatter in the political consultant class of who's been reached out to by whom," Padilla added.

Indeed, as the 2020 race heats up and more Democrats hop in the ring, California already seems to be at the forefront of a number of candidate's minds.

U.S. Senator Kamala Harris launches her campaign for President of the United States at a rally at Frank H. Ogawa Plaza in her hometown of Oakland, California, U.S., January 27, 2019. REUTERS/Elijah Nouvelage

Democratic Sen. Kamala Harris of California, the state's former attorney general, kicked off her campaign with a massive rally in her hometown of Oakland, California, in late January. Roughly 20,000 people were in attendance.

With strong roots in California, Harris could have a big advantage over the growing field of Democratic contenders, but there have also been many examples of presidential candidates losing the primaries in their home states — such as Republican Sen. Marco Rubio losing in Florida in 2016.

Democratic Rep. Eric Swalwell, who represents California's 15th congressional district and is considering running in 2020, seems to recognize the value of having an earlier primary in his state, but also isn't discounting the importance of campaigning nationwide.

"It's great for California — as our most populous and diverse state, and as the world's fifth-largest — to have a stronger voice in the primary process, but it's not really a factor as I near my decision about whether to run for President in 2020," Swalwell told INSIDER. "If I run, I'm running for all Americans and seeking all Americans' support."

Democratic Rep. Eric Swalwell. Fox News/YouTube

Meanwhile, Democratic Sen. Cory Booker of New Jersey launched his bid for president on February 1 and has tapped Addisu Demissie as his campaign manager.

Demissie, who recently led Gavin Newsom to victory in California's 2018 gubernatorial race, has a proven record of success in the Golden State, as well as experience in presidential campaigns after serving in a key role on Hillary Clinton's 2016 campaign team.

Democratic Sen. Elizabeth Warren of Massachusetts also reportedly plans to visit California as part of a cross-country tour of early primary states, now that she's formally launched her presidential campaign.

This could be the start of a massive shift in candidate behavior, in which more and more contenders focus on the West in future elections.

"With California coming on early, I think the West is more important than ever," former Democratic Senate Majority Leader Harry Reid of Nevada recently told The Boston Globe.

'We're going to be a force for years to come'

California also held its presidential primary earlier in 2008, moving it up to February.

That year, the state saw its highest level of voter turnout for a primary election (57.7%) since 1980.

But that election was a one-off, and all of the other regularly scheduled primaries — for congress, state legislature etc. – remained in June.

As Sam Mahood, press secretary for Padilla, told INSIDER, "This isn't a one-off move up the primary, we've moved up the primary permanently so we're going to be a force for years to come."

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"Unlike 2008, this time around we’ve moved ALL regularly scheduled primaries up to March," Mahood added, meaning there are also important down-ballot races for Californians to vote on in next year's primary.

What could also change the game in California in 2020 is the level of enthusiasm for early voting.

In the 2008 California presidential primary, roughly 40% of voters sent in their ballots by mail. This seemed to limit the California primary's impact that year versus earlier contests in other states like Iowa and New Hampshire, despite the size of its electorate.

Comparatively, Padilla said that "for the last several election cycles ... it's been more than 60% of people who choose to vote by mail." California midterm voter turnout in 2018 was over 64%, the highest percentage since 1982, and roughly 65% of voters sent in their ballots by mail.

Mail-in ballots for the upcoming congressional election in Orange County wait to be inspected by election workers at the Orange County Registrar of Voters in Santa Ana, California, U.S. October 30, 2018. Mike Blake/Reuters

'I think an early primary is ... good for the policy and direction of our nation'

The major political parties in the US have strict rules surrounding the nominating process for president. In light of this, whenever big states move up their primaries it has the potential to cause backlash among party leaders.

In 2008, for example, when Florida and Michigan moved up their presidential primaries without the Democratic National Committee's (DNC) permission, their delegates were given just half a vote each at the party's national convention as punishment. For the same reason, the Republican Party issued a similar punishment for delegates to its national convention from Florida and Michigan that year.

With that said, California has not broken any rules by permanently setting an earlier primary date in this instance, given it falls in line with Super Tuesday and primaries in most other states.

But the news of the California primary being moved up permanently might spark concerns among some it will give an outsized influence to a coastal state, as well as a disproportionate advantage to candidates with lots of money.

But Padilla dismissed such fears, noting that he's often heard similar concerns about smaller states like Iowa and New Hampshire having so much sway over presidential nominees in such a large, diverse country.

"I think an early primary is not just good for California, I genuinely believe it's good for the policy and direction of our nation," Padilla said.

"California has prided itself in being a policy leader on a lot of fronts and for a lot of years," he added. "We look forward to continuing to be a driver of policy and the economy for the country."