Does anyone know the law with respect to free speech rights of other non-corporation groups of individuals? For instance: labor unions, churches, charities, "co

Does anyone know the law with respect to free speech rights of other non-corporation groups of individuals? For instance: labor unions, churches, charities, "community organizing" organizations... hell, political parties? Are these groups presumed to have free speech rights that extend from the free speech rights of their members, or is the government allowed to restrict them?