In true California tradition, voters in San Francisco gave themselves the right Tuesday to take more votes in the future, this time determining the fate of individual real estate developments on the city's waterfront.

Fifty-nine percent of voters supported Proposition B, the evocatively named Waterfront Height Limit Right to Vote Act. The basic idea behind it sounds democratic: If real estate developers want to build denser or taller than has historically been allowed on property now managed by the Port of San Francisco — a part of the city with height limits regularly zoned around 40 feet — they'll have to get approval straight from the voters to do it.

In theory, this takes power from generally unpopular developers and places it in the hands of the public instead. In reality, however, it yanks influence from a very different group: city professionals whose full-time job it is to weigh the insanely intricate implications of new development for affordable housing, property-tax coffers, economic development, public benefits, transportation infrastructure and more.

It's the job of professional planners, in other words, to assess projects for the benefit of the entire city, from the perspective of many competing interests. It's hard to expect — or even ask — voters to do that.

"The planning process involves a lot of complicated tradeoffs, whereas the ballot process involves simplistic slogans," said Gabriel Metcalf, executive director of the San Francisco Planning and Urban Research nonprofit that opposed the ballot measure.

The slogan used to rally support for Proposition B: No wall on the waterfront.

Imagine if, in rapidly growing cities such as Washington — a place that already wrestles mightily with its own height limits — every new development requiring the city to rezone a parcel of land demanded a ballot measure first. In San Francisco, if voters frown on a project, a developer can amend the plans. But those amended plans face yet another public vote. And a more likely outcome is that developers may shy away from this entire process all together.

The fate of new developments that do go to the public will hinge on the same questions at play in any ballot measure: What else is on the ballot? Who is funding the public campaigns for and against a project? How much money are they spending to do that? And who will actually turn out to vote? (In a city of 840,000 people, only 90,000 actually weighed in on Proposition B.)

"These things will all influence whether a project moves forward in the first place, and so you have essentially politicized the development process," says Jason Jordan, director of policy for the American Planning Association, who has not seen a policy before exactly like this one. He means by this that the planning process will become politicized to a degree well beyond what it already is. "I don't know if that’s going to lead automatically to better or more inclusive outcomes. I can guarantee that it will lead to more expensive outcomes."

Local government has to pay to put on these votes. Developers will have to invest more money into projects that will now entail an expensive ballot campaign. Those costs, inevitably, will be baked into the price of new housing —  if it's ever built.

"The worrisome aspect of this for housing affordability is very, very real," Jordan says. The APA had similar concerns about a failed constitutional amendment in Florida a few years ago — the "Hometown Democracy" amendment  — that would have turned more decisions about development growth over to voters.

If Proposition B does make housing more expensive in San Francisco, that would be an ironic outcome for affordable-housing advocates who backed the proposal, alongside the Sierra Club.  Together, they lobbied against "luxury condo builders" encroaching on the city's public waterfront. Their advocacy extends from a long tradition of opposition in San Francisco to the kinds of development — glass-covered condos, mega-mixed-use developments, tall office towers — that are common to so many other U.S. skylines.

"I've been to Toronto, to Miami," says Jon Golinger, campaign director for No Wall on the Waterfront. "While there’s certainly plenty of beauty on those waterfronts, by and large they're blocked off by tall buildings, and the people who live in them benefit the most. San Francisco has retained our open nature on the water because of a series of battles like this one, as well as because of the height limits."

That tradition, though, has also contributed to a housing crunch in one of the least affordable cities in the country (for a great history on this, read this TechCrunch primer.) The height limits along the waterfront are low relative to many big cities. And San Francisco has remained particularly stingy about granting new building permits for housing construction even as demand to live in San Francisco has grown.

"There have been anti-growth attitudes for a really long time, so we’ve made it very difficult to add to the housing supply," Metcalf says. "What’s so sad about this is that a set of wealthy homeowners who live on top of hills and have views were able to harness the fear and frustration that lots of people feel about housing affordability for a ballot measure that is going to reduce housing supply and contribute to the very problems that people are struggling with."

Two waterfront developments that had been in the works — and that will now likely require public approval — would have brought as many as 3,000 new housing units to the city, with several hundred designated as affordable housing.

The city's plan was never to approve them without public input. That's why tortured public hearings and open-comment periods exist.

"This is not about whether the public should be involved in the process. It’s whether or not the ballot box is the best place to do it," Jordan says. "There’s a certain Pandora's box element to this. We don't know exactly what the implications are going to be. But it's probably safe to say that the advocates for them don't fully appreciate all the implications, either."