Full Idea
Exercise of political power is fully proper only when it is exercised in accordance with a constitution the essentials of which all citizens as free and equal may reasonably be expected to endorse in light of principles and ideals acceptable to reason.
Gist of Idea
Power is only legitimate if it is reasonable for free equal citizens to endorse the constitution
Source
John Rawls (Political Liberalism [1993], p.217), quoted by Andrew Shorten - Contemporary Political Theory 02
Book Reference
Shorten,Andrew: 'Contemporary Political Theory' [Palgrave 2016], p.23
A Reaction
This is not the actual endorsement of Rousseau, or the tacit endorsement of Locke (by living there), but adds a Kantian appeal to a rational consensus, on which rational people should converge. Very Enlightenment. 'Hypothetical consent'.