 The four theories of political obligation sketched above do not exhaust the possibilities – Dorota Mokrosinska, for instance, has recently advanced a “civil justice” theory in her Rethinking Political Obligation – but they seem to represent the main lines of argument. Indeed, even Mokrosinska acknowledges that her “argument from civil justice combines elements of both natural duty accounts and associative theories” (2012, p. 174). In fact, the search for a hybrid theory is something a number of philosophers have undertaken, either implicitly or explicitly, in recent years. Gilbert (2006) and Steinberger (2004), for example, seem to have developed hybrid theories without ever advertising them as such. Gilbert’s theory fuses the consent and associative approaches through her reliance on joint commitments to a plural subject, or group. For his part, Steinberger combines the consent and natural-duty approaches, arguing that any “generalized attempt to divorce obligations from natural duties, to find justifications for the former that are entirely independent of the latter, is … doomed to fail” (2004, p. 211). Wellman explicitly acknowledges the hybrid nature of his theory, which combines an appeal to the natural duty of samaritanism with reliance on the argument from fair play (Wellman 2005, esp. chap 2).