Updated June 12, 2018, 6 p.m.
One week after Election Day, Board of Supervisors President London Breed continued Tuesday to grow her lead over former state Sen. Mark Leno in the race for San Francisco mayor.
She now has 1,861 votes more than Leno, or 50.42 percent of the vote to Leno's 49.58 percent — a 0.02 percent change in Breed's favor since Monday.
Breed's edge grew Tuesday by about 200 votes as elections officials released their latest tally in the city's ranked-choice voting system. Elections officials tallied another 10,621 votes between Monday and Tuesday afternoons.
The San Francisco Department of Elections says it still has thousands of ballots to process, and it expects to continue reviewing ballots through the coming week. Updated results will continue being released daily at approximately 4 p.m.
City elections chief John Arntz says this is the closest election in the 16 years he's been in charge of the department. There are many reasons the count is taking as long as it has, he says, including the fact that the ranked-choice ballots require a separate card be fed into the machines, increasing the processing time by 25 percent, according to Arntz.
Arntz has until July 5 to certify the election, at which point it will go to the Board of Supervisors, probably at its first meeting after that on July 10, "which means July 11 would be when whoever gets the most votes could take office," Arntz said.
The closeness of this election has led to an unusual number of people coming to the basement of City Hall for the daily afternoon updates. "At a certain point the wave is gonna break on the shore, and we won't have people down here, and we'll still be doing work," Arntz said.
Leno led by about 1,000 votes at the end of counting on election night under the city's ranked-choice voting system, but Breed has gained ground with each updated count and eventually passed Leno on Saturday. She's continued to grow that lead, albeit slightly, every day since.
Breed has consistently held at least a 10 percentage point lead over Leno in first-place ballots. But Saturday’s count marked the first time that Breed led once second- and third-place votes had been reallocated. Ranked-choice voting allows voters to choose a first-, second- and third-place candidate in one race, creating an instant runoff of sorts.
Under ranked-choice voting, if no candidate gets more than 50 percent of the vote in the first round of counting, the last-place candidates are eliminated one at a time, and those voters' second-choice votes are redistributed. That means there can be multiple rounds of counting before a candidate emerges with a clear majority, as has been the case this election. It also means that the candidate with the most votes in the first round is not guaranteed a win.
Leno has received more than 42,000 second-place votes from voters who put Kim number one as of the latest count. That's more than three times as many Kim supporters that selected Breed as their second choice.
Tuesday's update also showed Kim moving within just a few thousand votes — and less than 1 percentage point — of Leno for second-most first-place votes. If she were to surpass him, it would be Kim and Breed picking up second- and third-place votes in the instant runoff.
The ranked-choice voting system further complicates what was already a whirlwind mayor's race.
The sprint for the mayor's office was set off in December 2017, when Mayor Ed Lee died suddenly, giving candidates just a month to decide whether to run for an office that was not supposed to be on the ballot until November 2019.
Lee's unexpected passing shook up the dynamics almost immediately: Breed, who had been considering a run for mayor, became acting mayor upon Lee's death, boosting her profile and perhaps cementing her decision to run. Then, when progressive supervisors allied with Kim decided to name moderate Supervisor Mark Farrell as interim mayor, Breed's base was electrified and she emerged from the entire affair as the apparent front-runner in a very abbreviated race.
In particular, Breed's popularity changed the dynamics for Leno, who'd been diligently preparing for a 2019 run but had to change course when the timeline was truncated.
Ultimately, Leno decided to throw his lot in with Kim, asking voters to list each of them as their number one and two choices.
Breed's campaign was embraced by the city's political establishment, including former Mayor Willie Brown and many tech executives, including investor Ron Conway, whose left-leaning critics see him as emblematic of a changing, gentrifying San Francisco.
Both Kim, who has always been counted among the progressive faction on the Board of Supervisors, and Leno, who has strong progressive credentials but was also a pragmatic state senator, ran to Breed's left.
In truth, all three major candidates are liberal Democrats with few significant policy differences between them. But in San Francisco, where housing policy is a flashpoint, Breed is seen as a moderate, more business-friendly Democrat who would be more likely to side with developers; Kim and Leno have cast themselves as more likely to extract concessions from builders around affordable housing.