To understand the mind-boggling, consequential power of just one vote in this year’s historic District 16 congressional primary, take a stroll through downtown Saratoga, the heart of Santa Clara County’s Precinct No. 4692.

You might bump into Linda Schaefer walking her shih tzu down Big Basin Way. She’s a conservative Republican who usually votes for like-minded candidates but said she’s had a lot on her mind lately, and when she filled out her ballot in the 11-candidate race to replace retiring Congresswoman Anna Eshoo, she bubbled in the circle next to “Evan Low.”

“Don’t ask me why, I just did,” Schaefer said on her walk last week. “Don’t even ask me if he was a Democrat or Republican. I don’t even remember.”

The impact of Schaefer’s single vote — just like the random or calculated decisions of the 182,134 other people who voted in California’s District 16 primary — helped forever intertwine the political biographies of Low, a 40-year-old state Assemblymember, with fellow Democrat Joe Simitian, a 71-year-old Santa Clara County supervisor.

When the vote count was finally completed last week after nearly a month of tallying ballots, Low’s and Simitian’s fight for second place resulted in a first — a dead-heat, 30,249-30,249, that propels both into November’s runoff election — unless someone comes forward in the next few days to pay for an expensive recount against former San Jose Mayor Sam Liccardo, who finished comfortably in first.

No place in the 529-square-mile, two-county congressional district came closer than Schaefer’s Saratoga to reflecting the exquisitely equal tally. Mail-in ballots from the residents among Precinct 4692’s stretch of bakeries, boutiques and yoga studios nestled in the foothills of the Santa Cruz Mountains split the vote between Low and Simitian 98-98. The 11 people who voted in person sided with Low, though, 6-5. Overall, the two candidates were separated by less than 1% in nine precincts.

But Low’s good fortune of winning an unlikely crucial vote from a Saratoga Republican didn’t help him in one Mountain View duplex. Cecilia Nelson, a 26-year-old mechanical design engineer, had been leaning toward Low, but with some extra research on her laptop over French Press coffee with her out-of-town boyfriend, she chose Liccardo instead because of his positions on housing and homelessness.

“I think it’s crazy to think about something as simple — or someone as little as me — just choosing one candidate over another could cause this chain of events,” Nelson said.

The stunning finale is a congressional first for California since the state switched to a jungle primary system in 2012 where the top two vote-getters head to the general election regardless of their party. Since then, no House or Senate ballot has had three names on it in November, and on only one occasion have three names appeared for a state race.

“It’s a good time to buy a lottery ticket in #CA16!” Liccardo posted on social media.

In the 2016 primary election, Republican Marco Antonio Leal and Libertarian Baron Bruno — both write-in candidates — tied for second with 32 votes in the District 62 state Assembly race. Their opponent, Democrat Autumn Burke who won the seat for the second time that November, secured the top spot by a landslide 67,691 votes.

In Silicon Valley’s District 16 race, the dizzying path to the final results included countless lead changes that started on election night when Simitian prematurely celebrated with supporters at the Palo Alto Creamery, telling the Bay Area News Group, “the margin was wide enough” to put him into the November runoff.

But over the next 10 days, as more mail-in ballots poured in, the race slowly began to swing in Low’s favor until the former Campbell mayor finally found himself in the second spot. Over the next 2 1/2 weeks, the lead changed at least six times as more mail-in ballots arrived and rejected ballots that had signature issues were double-checked with the voter.

When Santa Clara County counted its last ballot Tuesday, Low led by only one vote. The next day, San Mateo County reported one last ballot that it had to verify late Tuesday — it went for Simitian.

“I would describe it as a you-got-to-be-kidding-me moment,” Simitian said. “It was altogether unexpected just by the virtue of the sheer size of the district and the number of votes cast.”

Simitian said Thursday he had yet to speak to Low since their tie became national news, but the two have bumped into each other at several events throughout the drawn-out saga and have marked the occasion with pleasantries and a hug.

When the results came in, Low was in Sacramento working at his job in the state legislature.

His first reaction: “Wait, what?”

Since then, people have reached out to him admitting they wished they did more or had registered to vote in the consequential election. On the flip side, he’s heard from voters who said Low knocking on their door made all the difference.

“So many people have reached out, people that I had not had the privilege to know before, voters from all over the congressional district who said because you knocked on my door, I was the deciding vote,” Low said. “The truth is, yes, every single one of you are correct.”

That door knock didn’t always translate into a vote. In downtown Saratoga, Low knocked on the door of MaryAnn Serpa, 70, and her partner of 43 years, Julie Mednick, who both mailed in their ballots.

“We were torn!” Serpa said.

They liked Simitian’s experience. They respected Low’s LGBT identity. And Serpa factored in what she found “endearing” about Liccardo: “his dad eats at La Mere Michelle,” a Saratoga landmark.

In the end, they split their votes between Simitian and Liccardo.

Melissa Michelson, a political science professor at Menlo College, said the tie is likely to generate a higher turnout in November as more voters realize the weight of their vote — especially in a blue state like California that is almost guaranteed to go for Biden.

“I think often in California because we’re not a battleground state in a presidential election it doesn’t feel like that much is going on,” she said. “It’s not like we live in Arizona or Nevada where the Democrats and Republicans are spending hundreds of millions of dollars and are inundated with ads. I think we’re going to see that level of campaigning for this House seat.”

It’s unclear who a three-way race will favor. Liccardo and Simitian both are considered moderate Democrats, while Low has branded himself as the progressive candidate.

Liccardo finished more than 8,000 votes ahead of his deadlocked rivals. The former San Jose mayor had strong backing in West San Jose and surprisingly finished first in San Mateo County even though Simitian once represented the area in the state Senate. Low carried most of Campbell, where he served as mayor and Simitian performed well in north Santa Clara County, which he represents on the board of supervisors. But will all the publicity of the dead heat help Low or Simitian?

And really, how easy is it to predict what’s in the mind of a voter?

Despite his lead, Liccardo doesn’t necessarily come into the three-way race “with any sort of advantage,” Menlo College’s Michelson said.

Turnout in the primary election was low — 37.39% in Santa Clara County and 40% in San Mateo County. Of the registered voters in the district, roughly 260,000 didn’t cast a ballot and Michelson said all three campaigns likely will be conducting robust voter turnout initiatives.

Liccardo, Low and Simitian also will have the chance to pick up votes, roughly 83,000, that went to the eight other candidates, and possibly the endorsements of those candidates themselves.

Finishing in fourth with 23,275 votes was former Menlo Park Mayor Peter Ohtaki, who was one of two Republicans in the race. While Michelson thinks it’s unlikely Ohtaki will back one of the three Democrats, other runner-ups, like Palo Alto City Councilmember Julie Lythcott-Haims, might. She finished with more than 11,000 votes.

“She’s pretty progressive,” Michelson said, “and probably cares a lot about which one of these three people win in November,”

Military veteran and tech entrepreneur Peter Dixon, who came in fifth with 14,673 votes, could also be a key endorsement as the political newcomer amassed the biggest war chest — nearly $2.8 million — though roughly half of that was his own money, and had the most outside financial backing from a super PACs.

Back in Saratoga, Jamie Wong, 66, said she voted for Low in the primary — she liked his statewide experience in Sacramento. But she’s considering Liccardo, 53, because of his experience lobbying in Washington, D.C. Besides, she said, “I’d rather have someone younger than Simitian.”

As for Serpa, who helps run the Aegis Gallery on Big Basin Way and struggled with her vote for Liccardo, she’s quite baffled about what to do in November.

“I really don’t know how to think now that the three will be up and two are tied,” Serpa said. “I have to rethink this.”