In January 2015, Christensen was appointed by San Francisco Mayor Ed Lee to fill the District 3 supervisorial vacancy left by former Board of Supervisors President David Chiu upon his election to the California State Assembly. In the closely fought supervisorial election in December 2015, she was defeated by Aaron Peskin, who had previously held the seat from 2001 until 2009. During the election campaign, Julie Christensen cited the physics concept “wormhole”—a connection between two different space-times—to describe the Stockton Street Tunnel connecting Union Square and Chinatown, Peskin's ally Rose Pak distorted the word “wormhole” to imply that Chinatown is a hole of worms, which successfully triggered the anger of some Chinatown residents. That negative press controlled by Rose Pak in Chinatown created an opportunity for Peskin to pick up much-needed votes in the Chinese community when he ran against Christensen.
