 The second way to defend public reason from the objection is to concede that the idea ought to apply to itself (Estlund 1998) and argue that it does so successfully. This strategy might be pursued in several ways. The proponent of public reason may point to some allegedly public or shared ideal—moral autonomy or respect for persons—and argue that this ideal both justifies a commitment to public reason and is publicly justifiable by virtue of being a suitably public or shared ideal. This strategy, however, faces two related challenges. If the ideal in question is formulated in a sufficiently detailed or rich way, such that a commitment to public reason is plausibly entailed by the ideal, then the ideal runs the risk of being one that is no longer suitably public or shared. This defense thus runs the risk of grounding public reason in some reasonably contested moral ideal or claim about philosophical truth, though some argue this is the only appropriate way to defend the idea (Estlund 1998). On the other hand, if the alleged ideal is pitched at a level of abstraction that ensures it does remain suitably public, it may no longer be obvious that the ideal does in fact entail a commitment to public reason (Wall 2002, 390–391). Alternatively, a proponent might argue that public reason can successfully meet its own test by appeal to a convergence form of justification. On this view, the idea of public reason is justifiable or acceptable to all the relevant members of the constituency because each member has his or her own nonpublic reasons to accept the idea. For example, all reasonable people might converge on the importance of the value of justice for nonpublic reasons, and then the advocate of public reason need only establish that justice, at least under conditions of reasonable pluralism, requires a commitment to public reason (see sect. 1.5 above). But this line of response may be vulnerable to the charge that it can only succeed by stipulation—by defining the relevant members of the constituency as those who converge on the importance of public reason (Mang 2017).