  This general explanatory template can be filled out in a number of ways. The best known (Dworkin 1986, also 2006, 2011) begins at the claim that what explains the role of institutional history in the identification and enforcement of rights and obligations is that government’s action should be consistent in principle—some version of the virtue of treating what’s morally like alike, perhaps ultimately to be explained by some combination of reasons of fairness and government’s special duty to treat citizens as equals.