Communitarianism is a broad term for the constellation of normative ethical views that state that membership in communities carries considerable moral significance and many moral rights and duties are membership-specific, i.e., they are defined in relation to the community. Communitarianism differs in nature from more “flat” universalistic normative ethical theories, such as libertarian or egalitarian theories.

There is considerable debate regarding what communitarianism implies for open borders. Communitarianism has been identified as one of the few widely held mainstream clusters of views that does not straightforwardly endorse open borders conclusions, and might be used to endorse restrictionist conclusions.

• The inferences a communitarian draws about migration depend significantly on what communities are considered morally significant. We can think of citizenism and territorialism as forms of communitarianism that place considerable weight on formal citizenship and geographical location respectively, and they can be used to draw strong restrictionist conclusions if appropriate side constraints are not introduced. On the other hand, forms of communitarianism that give weight to communities that are not defined by citizenship or geography (such as extended families, ethnic groups, religious groups, and other ideological or cultural communities) might support liberalizing many forms of migration (such as family reunification), without going all the way to open borders.
• Communitarianism also argues in a more “pro-migrant” direction. In particular, it argues strongly against forced deportations and other measures that separate families by force. It also argues in the direction of an easier path to citizenship.
• In a comment thread, the question of the extent to which communitarians support open borders in theory and practice was raised. John Lee’s comment (at the end of the thread) provided a summary of what leading communitarian philosophers have said:
  

  Wikipedia’s article lists 4 major communitarian philosophers: http://en.wikipedia.org/wiki/Communitarianism#Philosophical_communitarianism

  One is Walzer, who is I would argue is more or less in the open borders camp. MacIntyre is there too, I don’t have a clear picture of where he stands. Canadian philosopher Charles Taylor stresses the benefits of maintaining cultural identities, but otherwise seems very optimistic about the prospects of assimilating or amalgamating immigrants (he seems to lay particular stress on the possibility of an immigrant eventually identifying with an adopted culture, and a bit dismissive of cultural identification based on ethnic descent): http://www.prospectmagazine.co.uk/magazine/charles-taylor-philosopher-interview/

  Michael Sandel, the last of the four, is surprisingly hard to pin down. He’s engaged much more with the policy realm than the others, but his only easy-to-find statement on immigration was very critical of Gary Becker’s immigration tariff proposal — but on classic left liberal humanitarian grounds: “a market in refugees changes our view of who refugees are and how they should be treated. It encourages the participants — the buyers, the sellers and also those whose asylum is being haggled over — to think of refugees as burdens to be unloaded or as revenue sources rather than as human beings in peril.”

  Overall, although communitarianism’s premises in theory seem like they might be fertile ground for restrictionist conclusions, there doesn’t seem to be evidence of communitarian philosophers actually reaching such conclusions. In cases where they reach conclusions on immigration policy, they seem to lean in favour of borders that are more, not less, open compared to the status quo.

Related reading

• Comment thread on communitarianism (also linked to above).
• Communitarianism, open borders, and “prisoners of the food metaphor” by Nathan Smith, January 12, 2013, for Open Borders.
• The Ethics of Immigration by Joseph Carens relies heavily on communitarian arguments in the first ten chapters, where he argues for expanded migrant rights and moderate liberalization of migration assuming that it is morally permissible for states to control migration on a discretionary basis. Carens in fact supports open borders, so he deliberately works within a framework that he does not embrace. However, the conclusions he arrives at using communitarian reasoning are robust under the removal of the assumption that states may control immigration on a discretionary basis. See Vipul Naik’s review of Carens’ book, part 1 and part 2.