In practice, rent regulations have usually been designed to mitigate these ill effects. New construction is exempted, at least for a period of some years, and landlords are allowed to factor improvement and repair costs into rent increases. Cities can also enforce penalties for substandard housing quality.

More to the point, any supply-side solution is wholly inadequate to the time frame of a housing crisis, especially when housing doubles as a vehicle for speculative investment. Last year over one in four apartments in Seattle’s downtown core stood empty, yet renters saw little relief beyond a temporary pause in rising rents. It’s unclear what better idea opponents of rent regulation have to offer than “wait it out.” With tenants at imminent risk of homelessness or displacement, the only other obvious short-term fix is to subsidize their rents, through vouchers, for example. Considering the substantial expense of such a program, and the questionable wisdom of signaling to private landlords that the public will absorb their price increases, limiting rent hikes starts to look like the fiscally responsible choice.

What does the research say? For decades economists have dismissed rent control out of hand. But this near consensus may finally be cracking under the weight of the evidence, which on balance supports rent regulation as an imperfect but important tool.

In the mid-1990s, rent control in three Massachusetts cities was repealed by a statewide ban; landlords began making more improvements but also evicted thousands of tenants, and rents shot up across the board. A widely reported 2018 study concluded that San Francisco’s policies have protected tenants from displacement — “absent rent control essentially all of those incentivized to stay in their apartments would have otherwise moved out of San Francisco” — but also contributed to rising rents citywide, largely because condo conversions reduced the supply of rental housing. However, this effect arguably resulted from the law being too lax and loophole-ridden, rather than too strong: cities can ban or limit condo conversions, as Seattle once did; and if it weren’t for a 1995 California state law prohibiting “vacancy control,” landlords could be prevented from raising rents exorbitantly between tenancies. Rent regulation is also far from the only culprit when it comes to insufficient housing stock in San Francisco, a city notorious for strict zoning laws and other measures limiting the development of new housing.

Some benefits of rent control may be difficult to quantify. New York’s longstanding policies seem, in a way, to have domesticated that city’s landlord class. Edmund Witter, now at the Housing Justice Project in Seattle, was once a supervising attorney at the Legal Aid Society in New York City. “Landlords just wanted their money at some point — they weren’t in the game of throwing people out for the sake of it,” he recalls. “They treated renters as more of an equal class, whereas in Washington sometimes it seems like renters get treated as second-class citizens.” In New York, rents were predictable, and everyone was more relaxed — tenants, landlords, even the courts, which were loath to evict people if they were making any effort at all. Moving to Seattle, Witter was “shocked to see people get evicted for $100, and landlords hyperventilating about a late fee not paid on time.”