Two of the most fundamental human needs are food and housing. As a result, there are government programs to help people who might not be able to afford them. But the way those programs work is wildly different.

Imagine, for a moment, if SNAP—the federal program, formerly known as food stamps, that gives money to low-income people for groceries—was managed in the same way that American cities treat affordable housing.

First of all, local governments would suddenly have much more power over the program. Wealthy cities could decide that they wouldn’t give SNAP benefits to any of their residents, essentially banishing everyone who relied on them to feed themselves and their families to other parts of their metropolitan area. Those cities that did accept SNAP might have to cobble together many other different sources of funding to make it work, leading to wildly inflated food costs for people in the program.

In certain places, where the affordable-food crisis got really bad, cities might institute price controls—but only for people who were already poor and already living in the city when the controls were passed. All newcomers, no matter their income, would have to pay full price, which would be inflated somewhat to cover grocers’ losses on the people who paid less.

And when it came time for local governments to put in their own revenue, they wouldn’t just use general funds—they would levy “affordable-nutrition fees” on Whole Foods, boutique grocers, and fancy restaurants. They’d also create “inclusionary food” requirements, so that those grocers and restaurants had to donate 10 percent of all the food they sold to low-income people. Of course, there’d be no guarantee that those measures would cover everyone who needed assistance buying food, and so thousands of people would end up applying for just a handful of grocery baskets.

Housing and food are very different goods, and there are ways in which this is a bit of a strained analogy. (One crucial difference is that, unlike with food, some people can have a vested interest in others’ not getting the housing they need: Whether they’re right or wrong, some homeowners expect to see the values of their properties go down if public housing is built nearby.) But comparing housing and food does help illustrate some of the absurdities in the way affordable housing is controlled.

While policies directed at making food more affordable surely are far from perfect, they have several key advantages over those that try to make housing more affordable. Most crucially, SNAP is funded through general revenue streams, and its benefits are guaranteed to anyone whose income qualifies.

In contrast, much of the affordable-housing debate in many cities has focused on using impact fees, inclusionary zoning, or both, to extract resources from housing developers, who many accuse of creating the affordability crisis to begin with. But there are good reasons that’s not how food policy is conceived, and most of them apply to housing, too. To begin with, blaming developers for high home prices doesn’t reflect the actual reasons why some markets are more expensive than others. While it may make intuitive sense to many that greedy builders and landlords are ultimately responsible for the exorbitant rents they charge in places like San Francisco or Boston, for that to be true, it must also be the case that places like Phoenix and Memphis are so affordable because their developers and landlords are benevolent and self-sacrificing. And that seems a lot more far-fetched.

More importantly, though, by making local affordable-housing programs dependent on such a narrow base of revenue—rather than general funds—the number of households who receive help is limited to far below the number who need it. That’s explains situations such as 88,000 people applying for just 55 affordable units in New York City, or the fact that just 77 percent of Americans whose income qualifies them to receive housing assistance actually get any assistance. (Of course, other programs that are funded at the federal level, including Section 8 vouchers and the Low Income Housing Tax Credit, get their money from other sources. But those aren’t sufficient either, and so it matters if local policies intended to fill the gap are doomed to miss that goal.)

As long as there is such a fragmented, ad hoc approach to housing, those issues will persist. As housing affordability becomes a larger problem, there needs to be solutions that don’t just symbolically lift up a tiny fraction of those who need help, and that aren’t subject to the caprice of local governments that decide they don’t want to help anyone at all.

This post appears courtesy of City Observatory.