At least four current and former big city mayors are thought to be considering a bid for the White House when voters go to the polls in 2020. These candidates range from representatives of the progressive left like Bill de Blasio to more business-oriented mayors like Michael Bloomberg, who preceded de Blasio as mayor of New York City. Whether they know it or not, all of them owe some debt to a man who served as mayor of San Francisco for fewer than three years and who was killed 40 years ago this week.

George Moscone is now remembered outside of his hometown as the mayor assassinated along with Harvey Milk by a former colleague of Milk’s on the city’s Board of Supervisors on November 27, 1978. But Moscone’s impact and vision is much more significant than that.