The Political Autonomy Argument justifies the doctrine of public rules by appeal to its role in protecting political autonomy (Williams 1998: 244). If citizens have no clear sense of what the principles of justice demand of them, then they lack awareness of the moral constraints to which they are subject, and so are prevented from freely identifying with those constraints. A similar threat to political autonomy arises when principles of justice fail the test of verifiable compliance. If citizens are freely to identify with the constraints to which they are subject, it is important that they can recognise these constraints as a product of others’ compliance with principles of justice.