Abstract
In this paper, I distinguish two conceptions of solidarity, which I call solidarity as beneficence and solidarity as mutual advantage. I argue that only the latter is capable of providing a complete foundation for national universal health care programs. On the mutual advantage account, the rationale for universal insurance is parallel to the rationale for a labor union’s “closed shop” policy. In both cases, mandatory participation is necessary in order to stop individuals free-riding on an ongoing system of mutually advantageous cooperation.