For decades, Orange County was seen as a reliable Republican stronghold in a state that has otherwise drifted more and more toward to the Democratic Party.

But that all changed in November 2018, when Republicans lost four long-held congressional seats in the affluent, suburban county south of Los Angeles – part of the seven seats the party lost overall in California during the drubbing it took in the last midterm election – and the GOP’s defeat in districts it once took for granted had party leaders in the state doing a lot of soul searching.

It also had them mapping out early their plans to retake those seats come 2020.

“We’re focused on California and recruiting there,” Torunn Sinclair, a spokeswoman for the Republican National Congressional Committee, told Fox News. “Those districts stayed red in 2016 and we think they’ll go back that way again in 2020.”

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One way Republicans are planning for the 2020 general election is by endorsing their candidates early on in an effort to avoid any contentious primary battles that could divide conservative voters and draw on-the-fence voters over the Democratic ticket.

While the NRCC has not officially weighed in on who it favors to run for the congressional seats, the Republican Party of Orange County has already endorsed two out of four candidates in districts it lost in 2018.

“We’re fully invested in winning back all of the four seats that we lost last year,” Randall Avila, the RPOC’s executive director, told Fox News. “We’ve already endorsed candidates for two seats and we plan to endorse the other two very early as well.”

Young Kim, a businesswoman and former California State Assemblywoman, has already won the endorsement of the RPOC in her re-match against Democratic Rep. Gil Cisneros for the state’s 39th congressional district. Kim lost to Cisneros by just 7,600 votes in the race last year for the open seat.

Kim has also earned the praise of House GOP leader Kevin McCarthy, who has called her “one of the top recruits in the country for House Republicans.”

Orange County Supervisor Michelle Steel has also earned the backing of her county’s GOP as she challenges Democratic Rep. Harley Rouda for the seat in California’s 48th district.

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The RPOC has not yet weighed in on endorsing candidates in the other two races, although San Juan Capistrano Mayor Brian Maryott is expected to get the endorsement from the party soon as he challenges Democratic Rep. Mike Levin in the 49th district. There are currently five Republicans vying for a chance to unseat Democratic Rep. Katie Porter, the popular freshman lawmaker who represents California’s 45th district.

Republicans also admit that they were vastly out-spent by Democrats during last year’s midterms, with Democrats spending $34.6 million on Cisneros’ campaign alone. The GOP, on the other hand, spent a total of $16 million in the four races in Orange County.

“We’re making sure we can narrow that gap for this election,” Avila said.

Besides fundraising, Democrats also outpaced their Republican rivals in 2018 when it came to employing the controversial method known as ballot harvesting.

In 2016, then-California Gov. Jerry Brown signed into law AB1921, which legalized the practice. Previously, only a family member or someone living in the same household was permitted to drop off ballots for a voter, but the new allowed anyone – including political operatives – to collect and return them for a voter.

Despite there not being any hard figures available to correlate Democrats success last November with the practice, many observers say they witnessed people bringing in huge stacks of ballots on Election Day.

“Anecdotally there was a lot of evidence that ballot harvesting was going on,” Neal Kelley, the registrar for voters in Southern California’s Orange County, told Fox News. “People were carrying in stacks of 100 and 200 of them. We had had multiple people calling to ask if these people were allowed to do this.”

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Top Republican leaders in the state said that while they were aware of the change in the law, they were surprised by how successfully Democrats were able to use the practice to their advantage in 2018.

They have vowed not to get fooled again.

“We’re going to have to take advantage of this ourselves,” Jim Righeimer, the former Republican mayor of Costa Mesa, Calif. and a leading voice in the state GOP, told Fox News. “The Democrats just mechanically did what it takes to win and Republicans were totally caught off guard.”

Democrats, however, contest the argument that ballot harvesting and a big infusion of campaign funding were the sole keys to their success – arguing that a strong ground game, the shifting voter demographics in the state and an overall distaste for the Trump administration’s policies were the reason for the party’s landslide victory throughout California.

“We beat Republicans on the ground, fair and square,” Katie Merrill, a Democratic consultant, told the San Francisco Chronicle.

There was a huge upswing in Latino and young voters – both groups the skew toward the Democratic Party – turning out in 2018, with voters aged 18-24 grew 30 points, from 16 percent in 2014 to 46 percent in 2018. Among those 25-34, it grew by 33-points, from 17 percent to 50 percent, according to figures compiled by Capitol Weekly.

For Latino voters, the increase was even larger, as over 2.6 million Latinos voted, more than double the 1.1 million that voted in 2014, and among Latinos aged 18-34, there was a 400 percent increase, from 214,000 in 2014 to 838,000 in 2018.

Republicans admit that they have work to do when it comes to appealing to Latino voters, especially as the White House continues to push a hardline immigration agenda and ramp up security along the country’s southern border.

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“It’s pretty tough to get your message across when you’re labelled as the party that won’t let your family in,” Righeimer said.

To counter this, GOP leaders like RPOC’s Avila – himself a 29-year-old Latino – said that the party needs to move away from focusing on national issues and instead make the race about what matters to voters locally.

“Our candidates are making an effort to distinguish themselves from the president and talk more about localized issues,” Avila said. “You’re going to see a lot of focus on appealing to that demographic that looks more like us as a state overall.”