Representative Khanna, now 42, often seems at the center of a swirl of contradictions. His 17th Congressional District in Northern California is home to the headquarters of Apple and Google and some of the world’s richest people, including those like Facebook’s Sheryl Sandberg who supported his earlier campaigns. But Khanna fights for progressive causes like curbing income inequality (and for the presidential campaign of Sen. Bernie Sanders, which he co-chairs), has sponsored an internet privacy bill, and is pressuring the tech giants in his district to add jobs — not at home but in depressed areas of the Rust Belt or Appalachia.