But the newcomers — brandishing high-tech phone apps where an East L.A. map is covered with thousands of dots of voters who’ve been contacted and those who need to be re-visited — are building on months of work by local activists like Sarabia, a 49-year-old veteran community organizer and UCLA instructor. He supported Sanders in 2016, when he lost the California primary to Hillary Clinton, but said this campaign is different. Last year, the Sanders team reached out to create a network of Latino activists, including many not usually involved in elections. The most enthusiastic volunteers, he said, are the ones unable to vote — either because they are still in high school or because they are not U.S. citizens.