What's set to be the largest housing bond in San Francisco history could be tanked on the November ballot by vocal opposition from local labor leaders who are concerned about a union-related provision relating to such housing bonds.

On Friday, Mayor London Breed announced that a proposed $500 million affordable housing bond headed for the ballot would grow to $600 million thanks to some updated numbers from the City Controller’s Office. As the Chronicle reports, the Controller updated the amount of debt the city could support without having to raise property taxes — and this is the second time the bond has ballooned, after an updated projection of property tax revenues grew it from $300 million to $500 million in April.

The bond will need a 67% majority to pass, and while affordable housing is a popular cause among San Francisco voters, this may not be a shoe-in due to one highly influential voting block: labor.

As Mission Local explains, labor leaders are inclined to oppose the bond after discovering that a recently passed law does not include such housing bonds among projects that the city is required to enter into project labor agreements for. Now, while the vast majority (upwards of 99%) of labor used for public construction projects in San Francisco is union labor regardless, the project labor agreement law forces a particular collective bargaining process and bureaucracy for all projects undertaken in the name of "Public Work or Improvement." Bond-funded housing that will be operated by non-profits won't be covered, and therefore even though local unions stand to benefit enormously from $600 million flowing to "shovel-ready" housing projects, they look likely to mount an opposition to the bond in a show of power and solidarity.

Per Mission Local, a project labor agreement provides greater protection for union workers over the course of a project — forcing non-union tradespeople to be paid union wages, for instance — so this isn't completely counterintuitive.

But it is certainly a frustrating squabble to look at from the outside, with one labor leader suggesting the bond can easily be tanked at the ballot box with a bit of union opposition. "If you think they can pass this measure with 67 percent and not run a perfect campaign, I think you’ve got another thing coming," says the "veteran labor leader" to Mission Local.

So, if a labor-funded opposition campaign does kill this huge housing bond, we can chalk labor up among the forces working against affordable housing construction in San Francisco, even if their intentions may be noble.

It's not enough that NIMBYism still runs rampant and creates extraordinary delays for any housing project in SF. As this recent opinion piece in the New York Times puts it, following the recent delay tactic in passing SB 50, "Creating dense, economically and socially diverse urban environments ought to be a paramount goal of progressivism... Yet where progressives argue for openness and inclusion as a cudgel against President Trump, they abandon it on Nob Hill and in Beverly Hills."