John Rawls’s move from A Theory of Justice to Political Liberalism was motivated by his dissatisfaction with the account of stability offered in part III of Theory. Even members of Rawls’s well-ordered society need the assurance that, should they choose to maintain their sense of justice, others will do the same—members prefer to cooperate, but only if they are reasonably sure of others’ cooperation. This is the mutual assurance problem for stability. In recent for years, a growing number of theorist have argued that Rawls’s assurance mechanism, in the form of public reason, fails in societies marked by pervasive disagreement. These theorists have proposed convergence accounts as offering better solutions to the assurance problem. This thesis argues that the assurance convergence offers cannot be maintained because of the deep pluralism with which convergence theorists are rightly concerned.