Watch: The Laws and Policies Driving Up the Cost of Housing

A Vox explainer video posted earlier this month documents the shortage of affordable housing in the United States. The premise of the video: that rent is more expensive, and homeownership is less attainable, in cities around the country—not just the usual expensive suspects, like San Francisco and New York City.

More than just raising the alarms about how expensive housing is becoming, the video attempts at explanation of how the housing market got this way.

Among the forces at work, the article identifies an imbalance of supply and demand.

On the demand side, the unprecedented size of the Millennial generation, which is aging into prime homebuying years, is adding demand to the market. Historically low mortgage rates also make it cheap to borrow money, which induces demand into the market.

On the supply side, the article looks at the rate of new residential construction, which is lower than any time in the United States since the 1960s. In particular, the construction of smaller entry level housing has declined from historic levels.

The main argument of the video is to identify the big obstacle standing in the way of achieving a balance of supply with demand: the various laws and regulations that make it illegal to build more housing. Single-family residential zoning, or exclusionary zoning, is identified as the primary obstacle. Other zoning regulations, namely height restrictions, parking requirements, and minimum lot sizes, are also named.