National is a potential PolicyGraphic value with which to tag a policy. PolicyGraphics are tracked similarly to demographics in describing the scope and nature of a policy's adoption and implementation--where, at what level of government, and how commonly the policy is adopted, for example. The purpose of these tags will be to allow future users to filter for policies that are most salient for their jurisdictions. In other words, a city or county government official can search only for policies appropriate at the Local level, an urban school superintendent could search only for those policies appropriate for Urban areas, and so on.
For a list of this and other values, see Policy_Atlas:PolicyGraphics.