San Francisco’s latest election yielded a paradox. London Breed, the city’s pro-housing mayor, won re-election in a landslide. But her choice to represent her former district, Vallie Brown, lost narrowly to Dean Preston, who stands to exacerbate the Board of Supervisors’ already pronounced bias against housing.

The result echoes a contradiction at the heart of politics and public opinion in San Francisco, where far more officials and residents claim to support housing than are willing to welcome it to their neighborhoods.

The citywide mandate for housing seemed clear enough last week. The year after Breed narrowly defeated former state Sen. Mark Leno in the special election to finish the late Mayor Ed Lee’s term, she was elected to a full term with more than 70% of the vote. While she faced only token competition, the absence of a serious opponent was itself a testament to the political strength of a mayor who has pushed for more housing across the spectrum.

Moreover, Proposition A, a record $600 million affordable-housing bond championed by the mayor as well as the supervisors, passed with similarly overwhelming support. So did Prop. E, which will incrementally ease development of affordable and teacher housing.

Unfortunately, the latter was watered down at the behest of the supervisors, who killed the mayor’s more ambitious proposal to streamline the sclerotic bureaucracy and endless appeals that stymie residential development. The same board has gone out of its way to heap aspersions on the state Legislature’s most important housing bill and block residential projects that might detract from the city’s inconstant sunlight or its supposedly historic laundry assets.

It’s a miserable record in a city that can’t seem to stem soaring housing costs or homelessness, and Preston appears likely to make it worse. He generally opposes new market-rate housing, which is how the city’s self-appointed progressives couch their opposition to any housing that has the distinction of having any chance of ever existing.

Preston did call for building 10,000 units of 100% affordable housing over the next decade, a big promise he now has an opportunity to pursue. If he joins the majority of the board in obstructing affordable and market construction alike, he will fall woefully short.

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