As state legislatures meet in a year of inflated rents and record home prices, it remains abundantly clear that barriers to housing construction are causing affordability challenges. States play a vital role in setting the rules and incentives that influence whether localities decide to permit new housing construction. Overly restrictive local zoning is the fundamental cause of America’s housing shortage, and states can place limits on local zoning as well as reform the processes that make land use regulation a source of frustration for so many local officials and citizens.