Supporters of rent control argue that stable, long-term renters help create the sense of vibrancy that makes communities attractive (and expensive) in the first place. And they ultimately argue that the moral rights of existing residents take precedence over, or at least deserve a fighting chance against, the economic interests of new residents. 

"The argument for rent control should be distinguished from the argument for affordability per-se," says Joshua Mason, an economics professor at Roosevelt University, told Pacific Standard. "Long-term tenants who contributed to this being a desirable place to live have a legitimate interest in staying in their apartments. If we think that income diverse, stable neighborhoods, where people are not forced to move every few years, [are worth preserving] then we collectively have an interest in stabilizing the neighborhood."

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The analysis of rent control is among the best-understood issues in all of economics, and - among economists, anyway - one of the least controversial. In 1992 a poll of the American Economic Association found 93 percent of its members agreeing that ''a ceiling on rents reduces the quality and quantity of housing.'' Almost every freshman-level textbook contains a case study on rent control, using its known adverse side effects to illustrate the principles of supply and demand. Sky-high rents on uncontrolled apartments, because desperate renters have nowhere to go - and the absence of new apartment construction, despite those high rents, because landlords fear that controls will be extended?