An apartment in San Francisco's Mission district, courtesy of Flickr user David McSpadden under a Creative Commons license.

Earlier this week, city supervisors in San Francisco considered an emergency 45-day moratorium on the construction of new market-rate housing in the Mission district so that the city could, in theory, pause to ponder what's happening in its insane housing market.

The Mission has long been home to lower-income residents, many of them minorities, and the organizations and social services that work with them. Lately, though, luxury apartments have been rising in their midst to house the city's influx of wealthy tech workers. The resulting conflict has a fevered quality that's particular to San Francisco, but it's also about the same tensions — which become intertwined and conflated — arising in neighborhoods in Washington and Chicago and Boston going through similar change.

In one light, this fight sounds like it's primarily about affordability. If we build only high-end housing now in the Mission, or along 14th Street, or in Uptown, the argument goes, then the people who can't afford those new apartments or the rising rents on homes around them will be priced out. To housing advocates, construction cranes and luxury countertops then become symbols of a city growing too expensive for its own residents.

In another light, these debates sound like they're more about neighborhood character. Julia Carrie Wong, writing for SF Weekly, sums up this perspective:

Whether the moratorium is good policy or not, it will put a stop to the construction of buildings that make longtime residents in the Mission feel out of place and unwelcome. And that's why people want it so passionately.

This is an argument not so much about the cost of housing, but about the nature of change. And it raises a question worth asking if we're going to articulate what any moratorium or new housing policy is really supposed to do: Would longtime residents be OK with a changing neighborhood if they could stay in it? Maybe not all of them, but many?

If San Francisco (or Washington, or Chicago) required developers to include more affordable units in market-rate buildings, if cities incentivized the development of more affordable buildings within changing neighborhoods, if we ensured that some number of housing units there — 20 percent? 35 percent? — remained permanently affordable, would that be an acceptable resolution?

Or is the change itself — those new buildings, the wine bars on the ground floor, the shifting demographics on the sidewalk — as problematic as the effect it has on housing prices? Because if the answer is yes (and I don't discount that it might be), then we are talking about a conflict that reasonable housing policy alone can't solve (I do discount the idea that a permanent ban on new market-rate construction would be successful policy here).

Consider, for instance, a neighborhood — a hypothetical Mission district 10 years from now — where 30 percent of the residents live in below market-rate housing, and 70 percent live in more expensive units. Housing isn't the only good in a neighborhood that changes when the demographics do. The retail makeup will inevitably shift, too, and most of it will cater to that 70 percent. Now the grocery store is a Whole Foods, and the carry-out restaurants have been replaced by sit-down ones, and the cheapest beer on offer anywhere is $9 a bottle. Now the Salvation Army storefront and the barbershop where haircuts cost $7 a piece no longer exist.

In this scenario, we've preserved affordable housing, but the character of the community has undeniably changed around it. Now someone who has an affordable unit (without the luxury of a washer and drier) doesn't have a laundromat anywhere nearby.

I'm not making the case for why we shouldn't try to preserve affordable units in changing neighborhoods; I'm suggesting why residents and housing advocates might fear that's not enough. This is why "character" here is not simply a synonym for aesthetics (although in other contexts, if we're being honest, it is).

It's impossible to entirely untangle character from affordability. But the Mission moratorium debate in particular seems muddled on this front.

City supervisors voted Tuesday 7-4 in favor of the moratorium. The measure needed two more votes to pass, and so it now looks headed to a ballot measure in November. A moratorium then might be an emotional victory for housing advocates. But, in a city that debates housing with famously — and intentionally — slow deliberation, consensus on any great resolution in 45 days, or even 18 months, is unlikely (one suggestion for how to use that time: "a big debate about how we could build a whole bunch more transit").

And as many opponents have pointed out, a moratorium actually makes the affordability problem worse. San Francisco for years hasn't been building enough housing to keep up with demand, and that's a big part of why housing is so expensive now. Halt new construction, and you perpetuate that problem.

So, with those economics in mind, what end is a construction moratorium supposed to serve? Is the ultimate goal to preserve affordable housing in a changing neighborhood? Or to forestall that change all together? Or is this one neighborhood fight a proxy for a citywide affordable housing shortage?

Housing economist Jed Kolko suggested to me a tremendously helpful frame for thinking about these distinctions. What is the basic right are we trying to protect in these fights? Is it a right to affordable housing in increasingly unaffordable cities? Or is it a right to affordable housing in particular neighborhoods? Or is it a right to affordable housing in particular neighborhoods where the character and community remain familiar to longtime residents?

If the answer is ambiguous, these debates will be incredibly hard to resolve, on any time frame.