If the measure passes, it will be a major setback to a series of waterfront projects, including the Warriors arena and highrises planned for the seawall lots near AT&T Park. “This is not aimed at any one project,” Evans told me. “There have been developers asking to change the rules, and we want to say that they can’t do it without the voters approving.”

The measure would define the “waterfront” as all property controlled by the Port of San Francisco — a broad sweep that would take in not just the land on the Bay side of the Embarcadero but a good number of lots on the landward side.

The Warriors may give this one a shrug; they know there’s no way that arena is getting built without a public vote. Other developers, however, were and are hoping that the city’s current policy of allowing variances and exemptions for specific projects that don’t meet local zoning standards will just c0ntinue, and that development foes won’t be able to muster the resources to fight every single one.

This would add significantly to the cost of building anything along the waterfront that doesn’t meet existing (low) height limits.

It will be a challenge for Mayor Lee, who is already scrambling to deal with the politics of a city where the tenant majority is angry and frightened. The source of a lot of that voter frustration is the tech boom, which the mayor supports — and he’s trying really hard to say that we can have it both ways: Affordable housing and lots of new rich people who want to live in the Mission.

(Willie Brown, by the way, is under no such illusions; he just thinks the middle class should move to Oakland.)

So how’s he going to come down — and how will the supervisors come down — on a proposal that is (a) popular and (b) makes a fair amount of sense and (c) will make it more difficult for his allies in the development world?

Can he afford to become the mayor who sides not only with Ron Conway and the Google buses but with the developers and against the waterfront environmentalists?

It’s going to be a challenge to get this on the ballot — the supporters will need about 15,000 signatures by the second week in February. But the 8 Washington foes collected way more than that. It’s likely this will be on the ballot — and will be one of the defining issues in local politics in 2014.