UPDATE on June 12, 2018: Rocha’s lead grew from 551 votes Monday to 660 (or 20.71 percent) the following morning, according to county election officials. Oliverio trails in third with 12,636 votes (19.68 percent). Ballots still to be counted: 12,000 provisionals, 7,700 mailed in, 2,600 from precincts and 300 conditional registrations for a total of 22,600. 

Don Rocha’s lead over Pierluigi Oliverio for the runner-up spot in Santa Clara County’s District 4 supervisor race grew to 552, according to the latest round of preliminary election results Monday evening with 6 percent of ballots yet to be counted.

So far, that leaves Rocha with 20.54 percent of the vote (12,836) compared to Oliverio’s 19.66 percent (12,285) in the bid to challenge June primary frontrunner Susan Ellenberg (33.52 percent; 20,946) in the November runoff.

Oliverio, a former San Jose Councilman, ended last week’s election in second place. As the county Registrar of Voters continued its round-the-clock tally of provisional and mailed-in ballots, however, he lapsed into third place by the weekend.

Ellenberg, a San Jose Unified School District trustee, secured a formidable lead in the primary without the institutional backing of either labor or business, which put their money behind Rocha and Oliverio, respectively. So it will be interesting to see where those loyalties will lie in the lead-up to November.

If the runoff pits Ellenberg against Rocha, who terms out from the San Jose City Council this year, she’ll be up against labor.

If comes down to her and the Silicon Valley Organization-endorsed Oliverio, she’ll likely benefit from an anyone-but-him push from unions, which have long enjoyed majority support from the five-member Board of Supervisors.

This article has been updated with the most recent tallies. 

Source: Santa Clara County Registrar of Voters