When the device of the "original position" was invoked it was for the purpose of ensuring that principles of justice chosen would definitely not be based on considerations that uniquely favoured given parties. In fact, Rawls even assumes that the problem of future generations can be addressed by means of the device. In relation to the latter problem, the invocation of equal liberty has a special pertinence since it ensures the integrity not only of the parties in the position but continuing lines of descent from it. Rawls even goes so far as to claim that equal liberty of conscience is "the only principle" that the persons in the original condition can acknowledge by which he seems to mean the only one that they can agree to as a condition of anything (and everything) else.
Even were the parties in the "original position" convinced that the principle of utility need not compromise liberty still they could see the point of adopting the principle of equal liberty first in any case. This points to a way that the parties in the "original position" would be prompted to consider pluralist or "mixed" doctrines rather than the allegedly "monistic" one of utilitarianism. Further the principle of equal liberty of conscience meets the criterion of finality as it is not a principle, once adopted, that can be bent in favour of something else. The "veil of ignorance" strengthens the case for its adoption since it ensures one has no means of knowing whether one would have views that were in the majority.
The discussion of future generations furthers the case for equal liberty since the adoption of the principle is one that members of other generations can be assumed to also desire for the same reason that parties in the original position would do so. It also meets the test of a reasonable paternalism in being a principle that we can assume those under our guardianship would adopt on attainment of the age of reason.
Having presented the basic argument for the principle of equal liberty Rawls goes on to discuss toleration. Liberty of conscience is something that can be restricted under special circumstances that involve severe threats to public order and security. However these are the only conditions as there is nothing in political authority strictly considered that provides it with competence in other domains. The restriction of liberty in the severe circumstances mentioned would be accepted within the original position since disruption of the conditions of liberty is a danger to all. Hence restriction in these cases is an "enabling right" in relation to the provision of liberty itself.
It follows from this point that toleration is a general consequence of the acceptance of the principle of equal liberty. Hence granting it is granting something that is just, denying it is unjust. As Rawls puts it in a very Kantian formula: "Liberty is governed by the necessary conditions for liberty itself". This formula echoes the universal principle of right in the Doctrine of Right that referred to freedom in accordance with a universal law so that "the freedom of choice of each can coexist with everyone's freedom" (Ak. 6: 230).
After arriving at this point Rawls concludes by providing some reasons why toleration should even extend to the intolerant despite the fact that intolerant groups would have no right to complain where toleration not to be extended to them. No particular view of religious truth can be accepted in the original position so there is no basis for anyone thinking that their own views have any privileged status. One of the nice points Rawls makes in this connection is that even the intolerant principle that all should obey the injunctions of God at the expense of anything else is indeterminate in the sense that no one has a status that politically can enable them to determine what these injunctions consist in.
The political basis for toleration of the intolerant consists, fundamentally, however, in the stability of just institutions in the sense that they reproduce adherence to themselves. This psychological truth about just institutions is one that should give members of a well-ordered society confidence in these institutions. The only case in which the intolerant have toleration withdrawn are where their intolerance poses danger to the whole body politic (and hence this is not a special principle applied to the intolerant).