the withdrawal of the philosopher to his original position* represents his attempt to leave behind the role of citizen, to achieve the kind of standpoint that gives one's conclusions a status, as “truths”, superior to the mere opinions of one's political community.
Mulhall and Swift, re:Michael Walzer on John Rawls. Walzer says that political values are culturally specific, negotiated among a society. Seeking a "true" answer outside of the context of social negotiation will be taking a questionable position of power.
*The "original position" is part of Rawls's theory of justice; it's the decision-making position of a hypothetical individual who is asked to determine rules of social cooperation without knowing any of their own particulars. Some (that is, most thinking people i know) would object that this individual would have no basis for making decisions without cultural context. I guess that makes me a communitarian.