The language policy of a liberal democratic state must be formulated in a context of multiple, often conflicting sets of interests and of normative constraints that limit the means by which the liberal state can manage these interests. The interests at stake are, first, those of the individual, for whom language is viewed both instrumentally, and as a matter of identity. The state has an interest in homogenizing the linguistic repertoires of its members to a degree sufficient to achieve the functions that states must by their very nature serve. To the extent that it views itself as just, it must also respond to the demands for linguistic diversity that emerge, for example, in federal and in postcolonial contexts. Finally, there may be an interest shared by all humans in preserving linguistic diversity. These sets of interests predictably generate conflicts, which a broadly liberal state must manage while respecting the normative constraints of state neutrality, and of individual rights. The justification of language policies that constrain and shape the linguistic repertoires of individuals through moderately coercive means that best satisfies these constraints appeals to state constraints on language choice as permitting the resolution of a collective action problem. [This paper was presented at the Annual Conference of the American Association for Applied Linguistics in Portland, Oregon, in March 2014.]