Housing prices are rapidly climbing in many American urban areas, pushing low‐income and sometimes even middle‐income people out of rental and home buying markets. American homeownership rates have fallen to the lowest levels since 1965, increasing wealth inequality and reducing productivity. Should urban areas respond to this affordability crisis by “growing up,” that is, building higher densities in the existing urban footprint as recommended by a recent White House policy paper? Or should they “grow out,” that is, build more developments at market densities at the urban fringe? Join three housing policy experts in a discussion of this question that is critical to the future of American cities.