The keys to the kingdom of the married might have been held only by private citizens—religious bodies and their leaders, families, other parts of civil society. So it has been in many societies throughout history. In the United States, however, as in most modern nations, government holds those keys. Even if people have been married by their church or religious group, they are not married in the sense that really counts for social and political purposes unless they have been granted a marriage license by the state. Unlike private actors, however, the state doesn’t have complete freedom to decide who may and may not marry. The state’s involvement raises fundamental issues about equality of political and civic standing.