Abstract
There are entitlements, opportunities, and rights presently reserved to married couples by the basic structure of society, its major social institutions. Some claim that this is as it should be. But given the abiding effects of the basic structure on the prospects of individuals living within it, restrictions on liberty built into the basic structure require justification. One might think that we could justify reserving the benefits of marriage to married couples by appealing to harm prevention. In this paper, I argue that the prospects of doing so successfully are dim.