The first time Democrat T.J. Cox faced Republican David Valadao in a primary election for California's 21st Congressional District seat, in 2018, Valadao won by a whopping 26 percentage points.
Eight months later, however, Cox eked out a narrow victory, winning by fewer than 900 votes.
Local Republicans attribute that dramatic turnaround to two factors: Democrats’ higher turnout for the general election and a campaign tactic called “ballot harvesting,” which had been illegal in California until former Gov. Jerry Brown made it lawful in 2016.
The question now is whether those things will happen again — and whether ballot harvesting will help either side win — after preliminary results from Tuesday’s election show Valadao ahead by 15 points.
Expectations are that November's presidential election will again attract a strong Democratic turnout at the polls. And the party has already said it will again collect and turn in voters' mail-in ballots.
The difference this time, though, is that the Republicans may follow Democrats' lead on the harvesting of ballots.
Some Republicans have looked askance at the practice. It is a controversial tactic some say can open the door to manipulation of votes.
But the party isn't going to sit idly by while Democrats persuade reluctant voters to turn over their ballots for delivery to poll boxes, Clayton Campbell, an executive committee member of the Kern County Republic Central Committee, said several weeks before this month's primary election.
Valadao, for his part, said in a Feb. 7 phone interview that Republicans needed to "take harvesting ballots more seriously" than the party did in 2018.
"It's something that we're going to have to find a way to do ourselves," said Valadao, a Hanford dairy farmer who served three consecutive terms in the House of Representatives before being unseated by Cox, a Fresno businessman.
In November's general election, the stakes will be very high in the 21st District.
Cox's victory in 2018 helped Democrats regain control of the House. Forty Republican seats swung to Democrats. Seven of those seats were in California, including the 21st District, which covers portions of Fresno, Kern, Kings and Tulare counties.
If Republicans do retake the House, then Bakersfield Republican Kevin McCarthy, now the House minority leader, could become speaker of the House, putting him second in the line of presidential succession.
The race is important enough that President Donald Trump flew to the Bakersfield area last month and made a special point of supporting Valadao, who he called "an incredible guy" who's "going to be fantastic" if he wins election in November.
University of Southern California political scientist Christian Grose, a specialist in political campaigns, called Cox's victory "one of the biggest shockers" in the entire 2018 election.
Among the many reasons Cox prevailed, Grose said, was late-arriving votes, which he called common among Democratic voters. Also, 2018 was a "very Democratic year" that saw many Republican losses, he added.
"Regarding 'ballot harvesting,' or collecting of mail ballots to drop off, this could have played a role if one party is better at it than another," Grose said.
The chairman of the Kern County Democratic Party, Ricardo Perez, said party workers will again go out to rural areas, greeting first-time and Spanish-speaking voters, and explain the election process in a transparent way.
He said they will make sure the ballot envelope is signed, as required by law, and see that no vote-tampering takes place.
"I don't think it is unseemly," Perez said. "We're enabling voters to exercise their constitutional right to cast their vote and have their votes be counted in elections."
He added that ballot-harvesting sends a message that the party engages with new voters in a way that makes voting easier to do.
"In 2018," he said, "Democrats outworked Republicans and we're going to do the same in 2020."
Local Republican Party officials did not respond last week to requests for comment for this story.
Valadao's campaign declined to address the question of whether its workers will harvest ballots this year. But it did reference the practice indirectly in an email Friday.
"Central Valley voters are supporting David Valadao because they want a member of Congress representing them who can work across the aisle and make them proud, not any campaign tactics," the statement read.
Cox's campaign manager, Amanda Sands, also declined to say whether people working on the candidate's behalf will harvest ballots in November. But she said by email that "there's no campaign tactic in the world that can save" Valadao in the November election.
Ivy Cargile, assistant professor of political science at Cal State Bakersfield, emphasized there were other factors, besides ballot-harvesting, that gave Cox an edge in 2018.
Cox made appearances on Spanish-language media early — sooner than Valadao did — to promote his candidacy, Cargile said. Additionally, Cox was able to tie his opponent to support for Trump, who that year was politically unpopular among local Hispanics, she said.
Hispanics were also energized and ready to vote, she added, and "that can help Democrats in down-ballot elections."
Cargile said ballot-harvesting can appear questionable — "the optics aren't good" — because it's easy for opponents to call ballots into question.
She said it's quite possible Valadao will learn from what happened in 2018 and make adjustments, such as getting in front of Spanish speakers sooner.
"That's extremely possible," she said, adding November's election could be extremely competitive, "which is good."