 Some of the more recent literature focuses on how contractarian theories can ensure the fairness and impartiality of the initial bargaining situation without appealing to any external, independent moral norms as the contractualist does. For the contractarian, all moral norms are supposed to be the result of agreement by rational agents, but if the contractarian has to appeal to prior moral norms in order to secure agreement then it’s not clear what sort of work the agreement is actually doing in establishing the content of the moral norms. At the same time, if there are no constraints at all over the initial situation then the outcome agreed to may fail to be a moral outcome, and may instead be an outcome according to the principle, as Rawls puts it, “to each according to his threat advantage” (1971, 141). Two potential strategies are to argue that assumptions designed to ensure the fairness and impartiality of the initial situation, such as the assumption that the contractors are symmetrically situated, either follow as a condition of rationality or are justified on strategic grounds. The idea that certain assumptions like symmetry follow as implications from the exercise of rationality has attracted recent criticism on grounds that such assumptions represent substantive constraints theoretically inaccessible to contractarians (Thrasher 2014). Others have attempted to defend the presence of such assumptions in contractarian theory (Thoma 2015).