I wrote an op ed for Law360,com that was posted today. While it is behind a paywall on Law360, it reads in full as follows:

3 Housing Riddles For De Blasio

As Mayor-Elect Bill de Blasio is making the transition from campaigning to governing New York City, it is worth contemplating some of the fundamental riddles that perplex those who spend their time thinking about the city’s housing policy. I address three of the most perplexing below.

The Riddle of Mandatory But Not Sufficient

The housing policy centerpiece of the de Blasio campaign is to require developers to build some affordable housing units when they build on lots that have been upzoned, a policy known as mandatory inclusionary zoning. The campaign website states that this policy will create 50,000 new units of housing.

Let’s put aside the fact that this number appears to be very aggressive given the lack of significant upzonings on the horizon (see second riddle below). Just because the city mandates that affordable housing be part of any new construction, it cannot mandate that developers build any housing at all if the deal does not make economic sense for them.

The de Blasio administration will need to carefully calibrate the mandatory inclusionary zoning rules to ensure that builders are sufficiently incentivized to build in the first place. This may limit the amount of affordable housing that can be mandated as part of that new construction.

One key aspect of this policy is whether the mandatory affordable housing will be required to be on-site or if the developer can build it off-site. If it is the former, it will help achieve the progressive goal of increasing socio-economic diversity in a city that is rapidly losing it.

But each unit of on-site housing would likely be more expensive to construct than off-site affordable units. And the opposite is true if the mandatory affordable units are allowed to be off-site; they will be likely cheaper to construct and thus more housing could be built. But it would not work toward increasing socio-economic diversity in the city.

And thus, the riddle of mandatory but not sufficient poses two challenges to the administration. Can it incentivize the creation of a meaningful number of units? And should it favor socio-economic diversity or the maximum production of affordable units? No easy answers here.

The Riddle of Now Versus Later

Can you increase the supply of housing to address the needs of a growing population while also downzoning large swaths of the city to respond to the preferences of the city’s current residents?

The Michael Bloomberg administration wanted to have this both ways, but that can’t work. The Bloomberg administration had planned on an increase in population of roughly another million people by 2030 while at the same time downzoning a large swath of the city (and, to be fair, upzoning some other portions).

This downzoning made current residents happy as it kept big, modern, out-of-context buildings from popping up near their homes. But it also limited the opportunities for increasing the housing stock, particularly near transit hubs. This is the basis of the second riddle — what is seen as bad by current residents may be good for future residents.

It is a fundamental economic truth that if more and more people are flocking to New York City, housing costs will rise unless supply increases. But for city residents, there is a paradox. New Yorkers see gleaming towers rise in their neighborhoods along with the rents for their nearby apartments. There are two explanations for this paradox.

First, the supply of new housing may be increasing without keeping pace with rising demand. Historically, New York City has not had many new units of housing built each year, maybe 20,000 units or so in a good year. This modest increase in supply has been overwhelmed by the increase in population of a million people in the last 20 or so years. This disparity goes a long way to explain the high rents and the miniscule vacancy rates that are seen throughout the city.

Second, new housing in one community (Williamsburg, for example) may be causing or be part of a wave of local gentrification in the existing housing stock. So, even if the new housing is having a tendency to decrease housing costs in the city overall because it increases the supply, it can also be pushing rents higher in the communities in which it is situated.

Increasing the supply of housing has to be a key component of providing “safe affordable homes for all New Yorkers,” as de Blasio calls for on his campaign website. This has to mean zoning significantly more land for high-rise residential construction as well as incentivizing the construction of affordable housing units in that new construction.

At the same time, de Blasio must attend to the concerns of those negatively impacted by the new construction. Hence, the riddle of now versus later.

The Riddle of the Few Versus the Many

The de Blasio campaign website calls for “tighter standards that ensure subsidies meet the needs of lower-income families and are distributed equitably throughout the five boroughs.” Distributing affordable housing subsidies equitably throughout the city is important, but there is another equity issue — should the city heavily subsidize affordable housing for a small portion of those who are eligible or should it distribute resources more broadly and thinly among everyone who is eligible?

Fewer than 8 percent of low- and middle-income households receive a direct or indirect subsidy for an apartment (excluding public housing) while more than 20 percent live below the poverty line of $23,283 annually for a family of four.

Should the city’s limited resources be used to create a relatively small number of new affordable units or should some of them be used in ways that benefit a broader swath of low- and moderate-income New Yorkers, albeit more modestly?

Certain policies can address the needs of many, many more low- and moderate-income households than does heavily subsidized new construction that houses perhaps a few thousand low- and moderate-income households each year.

Examples of such policies include tax credits for low- and moderate-income households that put money in their pockets and increased enforcement directed against landlords who try to illegally drive their tenants out of rent-regulated units. On the other hand, without an affordable apartment, staying in NYC can just be untenable no matter what additional benefits the government may be able to provide through more broadly available programs.

Thus, the third riddle is — do you give a lot of help to a few or do you give a little help to the many? It’s like choosing between the rock and the hard place for policymakers and New Yorkers alike.

Mayor-Elect de Blasio and his team will have to struggle with these riddles, and more. The only thing that is clear is that there are no right answers and no easy answers when it comes to housing policy in New York City.

—By David Reiss, Brooklyn Law School

David Reiss is a professor of law at Brooklyn Law School. He concentrates on real estate finance and community development and writes about housing policy.